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/Upgrades/DeployToUpgrade.cs

@@ -22,7 +22,7 @@ namespace OpenRA.Mods.Common.Traits
 		[Desc("The upgrades to grant when deploying and revoke when undeploying.")]
 		public readonly string[] Upgrades = { };
 
-		[Desc("The terrain types that this actor can deploy on to receive these upgrades." +
+		[Desc("The terrain types that this actor can deploy on to receive these upgrades. " +
 			"Leave empty to allow any.")]
 		public readonly string[] AllowedTerrainTypes = { };