Fix server ignoring fallback for translatable components (#9134)

LICENSE.md

@@ -58,4 +58,5 @@ Jakubk15 <jakubk15@protonmail.com>
 Redned <redned235@gmail.com>
 Luke Chambers <consolelogluke@gmail.com>
 Emily <emilia.lopezf.1999@gmail.com>
+dawon <dawon@dawon.eu>
 ```

patches/server/0010-Adventure.patch

@@ -736,10 +736,10 @@ index 0000000000000000000000000000000000000000..2fd6c3e65354071af71c7d8ebb97b559
 +}
 diff --git a/src/main/java/io/papermc/paper/adventure/PaperAdventure.java b/src/main/java/io/papermc/paper/adventure/PaperAdventure.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..ecddb6fe55e8ee1ca3b163503dd62200ce2d7d04
+index 0000000000000000000000000000000000000000..badde58c5151f838faa4b42db02e767eafa2da18
 --- /dev/null
 +++ b/src/main/java/io/papermc/paper/adventure/PaperAdventure.java
-@@ -0,0 +1,354 @@
+@@ -0,0 +1,355 @@
 +package io.papermc.paper.adventure;
 +
 +import com.mojang.brigadier.exceptions.CommandSyntaxException;
@@ -799,7 +799,8 @@ index 0000000000000000000000000000000000000000..ecddb6fe55e8ee1ca3b163503dd62200
 +                    }
 +                }
 +            }
-+            final @NotNull String translated = Language.getInstance().getOrDefault(translatable.key());
++            final @Nullable String fallback = translatable.fallback();
++            final @NotNull String translated = Language.getInstance().getOrDefault(translatable.key(), fallback != null ? fallback : translatable.key());
 +
 +            final Matcher matcher = LOCALIZATION_PATTERN.matcher(translated);
 +            final List<Component> args = translatable.args();