LUA and trait documentation fixes

- Typo in documentation ("proximitry").
- Add spaces between sentences.
- Remove most occurrences of "  " (two spaces) unless clearly used as indendation
- Punctuation (although no fullstop after filenames like "notifications.yaml").

OpenRA.Mods.Common/Scripting/Global/DateTimeGlobal.cs

@@ -26,7 +26,7 @@ namespace OpenRA.Mods.Common.Scripting
 			get { return DateTime.Today.Month == 10 && DateTime.Today.Day == 31; }
 		}
 
-		[Desc("Get the current game time (in ticks)")]
+		[Desc("Get the current game time (in ticks).")]
 		public int GameTime
 		{
 			get { return Context.World.WorldTick; }