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/Traits/Buildings/Bridge.cs

@@ -242,7 +242,7 @@ namespace OpenRA.Mods.Common.Traits
 
 			var ds = health.DamageState;
 			return (ds == DamageState.Dead && info.DestroyedTemplate > 0) ? info.DestroyedTemplate :
-				   (ds >= DamageState.Heavy && info.DamagedTemplate > 0) ? info.DamagedTemplate : info.Template;
+				(ds >= DamageState.Heavy && info.DamagedTemplate > 0) ? info.DamagedTemplate : info.Template;
 		}
 
 		bool killedUnits = false;