fix: wrong return in javadocs for bookmeta (#5579)

Closes #5574.
Reviewed-by: Mariell Hoversholm <proximyst@proximyst.com>

Spigot-API-Patches/0005-Adventure.patch

@@ -3261,10 +3261,10 @@ index f70a6a22b85ff0da76e67e9b223ad4e0b020b5c4..a15abec467bac70116a6fc21a300d493
 +    // Paper end
  }
 diff --git a/src/main/java/org/bukkit/inventory/meta/BookMeta.java b/src/main/java/org/bukkit/inventory/meta/BookMeta.java
-index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaaba2a0d18 100644
+index 94852d50e88d0594b84b581cd627174043629995..4947251f347d83fa326a67735293401c10d87ba4 100644
 --- a/src/main/java/org/bukkit/inventory/meta/BookMeta.java
 +++ b/src/main/java/org/bukkit/inventory/meta/BookMeta.java
-@@ -1,8 +1,11 @@
+@@ -1,8 +1,12 @@
  package org.bukkit.inventory.meta;
  
  import java.util.List;
@@ -3273,10 +3273,11 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
  import net.md_5.bungee.api.chat.BaseComponent;
  import org.bukkit.Material;
 +import org.checkerframework.checker.nullness.qual.NonNull;
++import org.checkerframework.common.returnsreceiver.qual.This;
  import org.jetbrains.annotations.NotNull;
  import org.jetbrains.annotations.Nullable;
  
-@@ -10,7 +13,7 @@ import org.jetbrains.annotations.Nullable;
+@@ -10,7 +14,7 @@ import org.jetbrains.annotations.Nullable;
   * Represents a book ({@link Material#WRITABLE_BOOK} or {@link
   * Material#WRITTEN_BOOK}) that can have a title, an author, and pages.
   */
@@ -3285,7 +3286,7 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
  
      /**
       * Represents the generation (or level of copying) of a written book
-@@ -119,6 +122,116 @@ public interface BookMeta extends ItemMeta {
+@@ -119,6 +123,117 @@ public interface BookMeta extends ItemMeta {
       */
      boolean hasPages();
  
@@ -3308,11 +3309,11 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
 +     * Limited to 32 characters. Removes title when given null.
 +     *
 +     * @param title the title to set
-+     * @return true if the title was successfully set
++     * @return the same {@link BookMeta} instance
 +     */
 +    @NotNull
 +    @Override
-+    BookMeta title(@Nullable net.kyori.adventure.text.Component title);
++    @This BookMeta title(@Nullable net.kyori.adventure.text.Component title);
 +
 +    /**
 +     * Gets the author of the book.
@@ -3330,10 +3331,11 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
 +     * Sets the author of the book. Removes author when given null.
 +     *
 +     * @param author the author to set
++     * @return the same {@link BookMeta} instance
 +     */
 +    @NotNull
 +    @Override
-+    BookMeta author(@Nullable net.kyori.adventure.text.Component author);
++    @This BookMeta author(@Nullable net.kyori.adventure.text.Component author);
 +    /**
 +     * Gets the specified page in the book. The page must exist.
 +     * <p>
@@ -3402,7 +3404,7 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
      /**
       * Gets the specified page in the book. The given page must exist.
       * <p>
-@@ -126,8 +239,10 @@ public interface BookMeta extends ItemMeta {
+@@ -126,8 +241,10 @@ public interface BookMeta extends ItemMeta {
       *
       * @param page the page number to get, in range [1, getPageCount()]
       * @return the page from the book
@@ -3413,7 +3415,7 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
      String getPage(int page);
  
      /**
-@@ -141,15 +256,19 @@ public interface BookMeta extends ItemMeta {
+@@ -141,15 +258,19 @@ public interface BookMeta extends ItemMeta {
       *
       * @param page the page number to set, in range [1, getPageCount()]
       * @param data the data to set for that page
@@ -3433,7 +3435,7 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
      List<String> getPages();
  
      /**
-@@ -157,7 +276,9 @@ public interface BookMeta extends ItemMeta {
+@@ -157,7 +278,9 @@ public interface BookMeta extends ItemMeta {
       * pages. Maximum 100 pages with 256 characters per page.
       *
       * @param pages A list of pages to set the book to use
@@ -3443,7 +3445,7 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
      void setPages(@NotNull List<String> pages);
  
      /**
-@@ -165,7 +286,9 @@ public interface BookMeta extends ItemMeta {
+@@ -165,7 +288,9 @@ public interface BookMeta extends ItemMeta {
       * pages. Maximum 50 pages with 256 characters per page.
       *
       * @param pages A list of strings, each being a page
@@ -3453,7 +3455,7 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
      void setPages(@NotNull String... pages);
  
      /**
-@@ -173,7 +296,9 @@ public interface BookMeta extends ItemMeta {
+@@ -173,7 +298,9 @@ public interface BookMeta extends ItemMeta {
       * 256 characters per page.
       *
       * @param pages A list of strings, each being a page
@@ -3463,7 +3465,7 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
      void addPage(@NotNull String... pages);
  
      /**
-@@ -195,8 +320,10 @@ public interface BookMeta extends ItemMeta {
+@@ -195,8 +322,10 @@ public interface BookMeta extends ItemMeta {
           *
           * @param page the page number to get
           * @return the page from the book
@@ -3474,7 +3476,7 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
          public BaseComponent[] getPage(int page) {
              throw new UnsupportedOperationException("Not supported yet.");
          }
-@@ -210,7 +337,9 @@ public interface BookMeta extends ItemMeta {
+@@ -210,7 +339,9 @@ public interface BookMeta extends ItemMeta {
           *
           * @param page the page number to set
           * @param data the data to set for that page
@@ -3484,7 +3486,7 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
          public void setPage(int page, @Nullable BaseComponent... data) {
              throw new UnsupportedOperationException("Not supported yet.");
          }
-@@ -219,8 +348,10 @@ public interface BookMeta extends ItemMeta {
+@@ -219,8 +350,10 @@ public interface BookMeta extends ItemMeta {
           * Gets all the pages in the book.
           *
           * @return list of all the pages in the book
@@ -3495,7 +3497,7 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
          public List<BaseComponent[]> getPages() {
              throw new UnsupportedOperationException("Not supported yet.");
          }
-@@ -230,7 +361,9 @@ public interface BookMeta extends ItemMeta {
+@@ -230,7 +363,9 @@ public interface BookMeta extends ItemMeta {
           * pages. Maximum 50 pages with 256 characters per page.
           *
           * @param pages A list of pages to set the book to use
@@ -3505,7 +3507,7 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
          public void setPages(@NotNull List<BaseComponent[]> pages) {
              throw new UnsupportedOperationException("Not supported yet.");
          }
-@@ -240,7 +373,9 @@ public interface BookMeta extends ItemMeta {
+@@ -240,7 +375,9 @@ public interface BookMeta extends ItemMeta {
           * pages. Maximum 50 pages with 256 characters per page.
           *
           * @param pages A list of component arrays, each being a page
@@ -3515,7 +3517,7 @@ index 94852d50e88d0594b84b581cd627174043629995..fdbd32c4bb6428f2dde484ecb53acdaa
          public void setPages(@NotNull BaseComponent[]... pages) {
              throw new UnsupportedOperationException("Not supported yet.");
          }
-@@ -250,7 +385,9 @@ public interface BookMeta extends ItemMeta {
+@@ -250,7 +387,9 @@ public interface BookMeta extends ItemMeta {
           * with 256 characters per page.
           *
           * @param pages A list of component arrays, each being a page