Add -shl and -shr to bitwise operators

Author: kborowinski

PowerShellSyntax.tmLanguage

@@ -311,7 +311,7 @@
 		</dict>
 		<dict>
 			<key>match</key>
-			<string>(?&lt;!\w)-(?i:band|bor|bnot|bxor)(?!\p{L})</string>
+			<string>(?&lt;!\w)-(?i:band|bor|bnot|bxor|shl|shr)(?!\p{L})</string>
 			<key>name</key>
 			<string>keyword.operator.bitwise.powershell</string>
 		</dict>