Fix #1262 Rename CreateCategoryAsync to CreateCategoryChannelAsync

Renames CreateCategoryAsync to CreateCategoryChannelAsync so that it is more
consistent with the naming with the naming of other channel creation
methods.

src/Discord.Net.Core/Entities/Guilds/IGuild.cs

@@ -480,7 +480,7 @@ namespace Discord
         ///     A task that represents the asynchronous creation operation. The task result contains the newly created
         ///     category channel.
         /// </returns>
-        Task<ICategoryChannel> CreateCategoryAsync(string name, Action<GuildChannelProperties> func = null, RequestOptions options = null);
+        Task<ICategoryChannel> CreateCategoryChannelAsync(string name, Action<GuildChannelProperties> func = null, RequestOptions options = null);
 
         /// <summary>
         ///     Gets a collection of all the voice regions this guild can access.

src/Discord.Net.Rest/Entities/Guilds/RestGuild.cs

@@ -177,7 +177,7 @@ namespace Discord.Rest
                 role?.Update(model);
             }
         }
-        
+
         /// <inheritdoc />
         public Task LeaveAsync(RequestOptions options = null)
             => GuildHelper.LeaveAsync(this, Discord, options);
@@ -777,7 +777,7 @@ namespace Discord.Rest
         async Task<IVoiceChannel> IGuild.CreateVoiceChannelAsync(string name, Action<VoiceChannelProperties> func, RequestOptions options)
             => await CreateVoiceChannelAsync(name, func, options).ConfigureAwait(false);
         /// <inheritdoc />
-        async Task<ICategoryChannel> IGuild.CreateCategoryAsync(string name, Action<GuildChannelProperties> func, RequestOptions options)
+        async Task<ICategoryChannel> IGuild.CreateCategoryChannelAsync(string name, Action<GuildChannelProperties> func, RequestOptions options)
             => await CreateCategoryChannelAsync(name, func, options).ConfigureAwait(false);
 
         /// <inheritdoc />

src/Discord.Net.WebSocket/Entities/Guilds/SocketGuild.cs

@@ -1079,7 +1079,7 @@ namespace Discord.WebSocket
         async Task<IVoiceChannel> IGuild.CreateVoiceChannelAsync(string name, Action<VoiceChannelProperties> func, RequestOptions options)
             => await CreateVoiceChannelAsync(name, func, options).ConfigureAwait(false);
         /// <inheritdoc />
-        async Task<ICategoryChannel> IGuild.CreateCategoryAsync(string name, Action<GuildChannelProperties> func, RequestOptions options)
+        async Task<ICategoryChannel> IGuild.CreateCategoryChannelAsync(string name, Action<GuildChannelProperties> func, RequestOptions options)
             => await CreateCategoryChannelAsync(name, func, options).ConfigureAwait(false);
 
         /// <inheritdoc />