support (pre) unary [ic]split/join operators

Author: msftrncs

PowerShellSyntax.tmLanguage

@@ -6674,8 +6674,27 @@
 					</array>
 				</dict>
 				<dict>
-					<key>reserve</key>
-					<string>#numericConstant</string>
+					<key>begin</key>
+					<string>[\x{2013}-\x{2015}-]((?i:join|[ic]?(?:split)))(?!\p{L})</string>
+					<key>beginCaptures</key>
+					<dict>
+						<key>0</key>
+						<dict>
+							<key>name</key>
+							<string>keyword.operator.unary.string-$1.powershell</string>
+						</dict>
+					</dict>
+					<key>end</key>
+					<string>(?=.|$)</string>
+					<key>applyEndPatternLast</key>
+					<true/>
+					<key>patterns</key>
+					<array>
+						<dict>
+							<key>include</key>
+							<string>#advanceToToken</string>
+						</dict>
+					</array>
 				</dict>
 				<dict>
 					<key>begin</key>