Stabilize and expose suggestions API (#1406)

* Expose suggestions API

* Improve javadoc of suggestions api

api/src/main/java/com/velocitypowered/api/command/CommandManager.java

@@ -7,8 +7,10 @@
 
 package com.velocitypowered.api.command;
 
+import com.mojang.brigadier.suggestion.Suggestions;
 import com.velocitypowered.api.event.command.CommandExecuteEvent;
 import java.util.Collection;
+import java.util.List;
 import java.util.concurrent.CompletableFuture;
 import java.util.function.Predicate;
 import org.checkerframework.checker.nullness.qual.Nullable;
@@ -116,6 +118,27 @@ public interface CommandManager {
    */
   CompletableFuture<Boolean> executeImmediatelyAsync(CommandSource source, String cmdLine);
 
+  /**
+   * Asynchronously collects suggestions to fill in the given command {@code cmdLine}.
+   * Returns only the raw completion suggestions without tooltips.
+   *
+   * @param source  the source to execute the command for
+   * @param cmdLine the partially completed command
+   * @return a {@link CompletableFuture} eventually completed with a {@link List}, possibly empty
+   */
+  CompletableFuture<List<String>> offerSuggestions(CommandSource source, String cmdLine);
+
+  /**
+   * Asynchronously collects suggestions to fill in the given command {@code cmdLine}.
+   * Returns the brigadier {@link Suggestions} with tooltips for each result.
+   *
+   * @param source  the source to execute the command for
+   * @param cmdLine the partially completed command
+   * @return a {@link CompletableFuture} eventually completed with {@link Suggestions}, possibly
+   *         empty
+   */
+  CompletableFuture<Suggestions> offerBrigadierSuggestions(CommandSource source, String cmdLine);
+
   /**
    * Returns an immutable collection of the case-insensitive aliases registered
    * on this manager.

proxy/src/main/java/com/velocitypowered/proxy/command/VelocityCommandManager.java

@@ -300,27 +300,14 @@ public class VelocityCommandManager implements CommandManager {
     );
   }
 
-  /**
+  @Override
-   * Returns suggestions to fill in the given command.
-   *
-   * @param source  the source to execute the command for
-   * @param cmdLine the partially completed command
-   * @return a {@link CompletableFuture} eventually completed with a {@link List}, possibly empty
-   */
   public CompletableFuture<List<String>> offerSuggestions(final CommandSource source,
       final String cmdLine) {
     return offerBrigadierSuggestions(source, cmdLine)
         .thenApply(suggestions -> Lists.transform(suggestions.getList(), Suggestion::getText));
   }
 
-  /**
+  @Override
-   * Returns suggestions to fill in the given command.
-   *
-   * @param source  the source to execute the command for
-   * @param cmdLine the partially completed command
-   * @return a {@link CompletableFuture} eventually completed with {@link Suggestions}, possibly
-   *         empty
-   */
   public CompletableFuture<Suggestions> offerBrigadierSuggestions(
       final CommandSource source, final String cmdLine) {
     Preconditions.checkNotNull(source, "source");