Allow setting IgnoreExtraArgs on an individual basis (#998)

* Allow setting IgnoreExtraArgs on an individual basis

* Remove passing in the flag as a separate parameter

* VS plz

* Push the RunMode setting out to its own attribute, because fox wants consistency.

Bonus: Removes the need for that godawful 'RunMode.Default'.

* Revert previous commit

* Fox doesn't like module-wide switches 😒

src/Discord.Net.Commands/CommandParser.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Immutable;
 using System.Text;
 using System.Threading.Tasks;
@@ -14,7 +14,7 @@ namespace Discord.Commands
             QuotedParameter
         }
         
-        public static async Task<ParseResult> ParseArgsAsync(CommandInfo command, ICommandContext context, bool ignoreExtraArgs, IServiceProvider services, string input, int startPos)
+        public static async Task<ParseResult> ParseArgsAsync(CommandInfo command, ICommandContext context, IServiceProvider services, string input, int startPos)
         {
             ParameterInfo curParam = null;
             StringBuilder argBuilder = new StringBuilder(input.Length);
@@ -110,7 +110,7 @@ namespace Discord.Commands
                 {
                     if (curParam == null)
                     {
-                        if (ignoreExtraArgs)
+                        if (command.IgnoreExtraArgs)
                             break;
                         else
                             return ParseResult.FromError(CommandError.BadArgCount, "The input text has too many parameters.");