Properly fix JavaDoc linting issues

Fixes our own, and upstream's, issues with the stricter Java 8 JavaDoc
linter.

Also removes the destroystokyo-release maven repository. I'm not sure
why I added it originally, but it's unnecessary now.

Spigot-API-Patches/Allow-Reloading-of-Command-Aliases.patch

@@ -6,7 +6,7 @@ Subject: [PATCH] Allow Reloading of Command Aliases
 Reload the aliases stored in commands.yml
 
 diff --git a/src/main/java/org/bukkit/Bukkit.java b/src/main/java/org/bukkit/Bukkit.java
-index 4a725d79..4c20a1be 100644
+index 4a725d79..498dfd33 100644
 --- a/src/main/java/org/bukkit/Bukkit.java
 +++ b/src/main/java/org/bukkit/Bukkit.java
 @@ -0,0 +0,0 @@ public final class Bukkit {
@@ -16,6 +16,8 @@ index 4a725d79..4c20a1be 100644
 +
 +    /**
 +     * Reload the Command Aliases in commands.yml
++     *
++     * @return Whether the reload was successful
 +     */
 +    public static boolean reloadCommandAliases() {
 +        return server.reloadCommandAliases();
@@ -35,7 +37,7 @@ index 3c550d06..4f077b7c 100644
 +    boolean reloadCommandAliases(); // Paper
  }
 diff --git a/src/main/java/org/bukkit/command/CommandMap.java b/src/main/java/org/bukkit/command/CommandMap.java
-index 30d60247..d8a75607 100644
+index 30d60247..938959aa 100644
 --- a/src/main/java/org/bukkit/command/CommandMap.java
 +++ b/src/main/java/org/bukkit/command/CommandMap.java
 @@ -0,0 +0,0 @@ public interface CommandMap {
@@ -45,8 +47,9 @@ index 30d60247..d8a75607 100644
 +
 +    // Paper start - Expose Known Commands
 +    /**
-+     * Return a Map (String -> Command) of Known Commands
-+     * @return Known Commands
++     * Return a Map of known commands
++     *
++     * @return known commands
 +     */
 +    public java.util.Map<String, Command> getKnownCommands();
 +    // Paper end