Refix Javadoc and readd getPlugin comments

src/main/java/emu/grasscutter/auth/ExternalAuthenticator.java

@@ -17,8 +17,8 @@ public interface ExternalAuthenticator {
      * Called when an external account creation request is made.
      * @param request The authentication request.
      *
-     * For developers: Use {@link AuthenticationRequest#getRequest()} to get the request body.
-     *                 Use {@link AuthenticationRequest#getResponse()} to get the response body.
+     * For developers: Use AuthenticationRequest#getRequest() to get the request body.
+     *                 Use AuthenticationRequest#getResponse() to get the response body.
      */
     void handleAccountCreation(AuthenticationRequest request);
 
@@ -26,8 +26,8 @@ public interface ExternalAuthenticator {
      * Called when an external password reset request is made.
      * @param request The authentication request.
      *
-     * For developers: Use {@link AuthenticationRequest#getRequest()} to get the request body.
-     *                 Use {@link AuthenticationRequest#getResponse()} to get the response body.
+     * For developers: Use AuthenticationRequest#getRequest() to get the request body.
+     *                 Use AuthenticationRequest#getResponse() to get the response body.
      */
     void handlePasswordReset(AuthenticationRequest request);
 }

src/main/java/emu/grasscutter/plugin/PluginManager.java

@@ -171,6 +171,11 @@ public final class PluginManager {
                 .toList().forEach(handler -> this.invokeHandler(event, handler));
     }
 
+    /**
+     * Gets a plugin's instance by its name.
+     * @param name The name of the plugin.
+     * @return Either null, or the plugin's instance.
+     */
     public Plugin getPlugin(String name) {
         return this.plugins.get(name);
     }