Improve upon Property Summaries in CommandServiceConfig (#839)

* Improve Boolean Property Summaries

Having the `CaseSensitiveCommands` property summary asking a question whenever Intellisense is invoked seems a bit nonessential instead of *properly* explaining what exactly it does. It would be better if instead, it stated it's use to be more comprehensible to the reader.

### Changes

- Edits the summaries of `CaseSensitiveCommands` and `ThrowOnError` to follow a more methodical convention for boolean property summaries (`Determines whether X ...` rather than `Should X be ... ?`).

This is just a small change to improve upon the current documentation, so it shouldn't conflict with anything.

* "DefaultRunMode should also be "Gets or sets blah blah blah" to be consistent."

src/Discord.Net.Commands/CommandServiceConfig.cs

@@ -2,17 +2,18 @@
 {
     public class CommandServiceConfig
     {
-        /// <summary> The default RunMode commands should have, if one is not specified on the Command attribute or builder. </summary>
+        /// <summary> Gets or sets the default RunMode commands should have, if one is not specified on the Command attribute or builder. </summary>
         public RunMode DefaultRunMode { get; set; } = RunMode.Sync;
 
         public char SeparatorChar { get; set; } = ' ';
-        /// <summary> Should commands be case-sensitive? </summary>
+        
+        /// <summary> Determines whether commands should be case-sensitive. </summary>
         public bool CaseSensitiveCommands { get; set; } = false;
 
         /// <summary> Gets or sets the minimum log level severity that will be sent to the Log event. </summary>
         public LogSeverity LogLevel { get; set; } = LogSeverity.Info;
 
-        /// <summary> Gets or sets whether RunMode.Sync commands should push exceptions up to the caller. </summary>
+        /// <summary> Determines whether RunMode.Sync commands should push exceptions up to the caller. </summary>
         public bool ThrowOnError { get; set; } = true;
     }
-}
+}