Update themes to accommodate C# grammar change (#192854)

See https://github.com/dotnet/csharp-tmLanguage/issues/290

extensions/theme-defaults/themes/dark_plus.json

@@ -77,6 +77,7 @@
 				"source.cpp keyword.operator.new",
 				"keyword.operator.delete",
 				"keyword.other.using",
+				"keyword.other.directive.using",
 				"keyword.other.operator",
 				"entity.name.operator"
 			],

extensions/theme-defaults/themes/hc_black.json

@@ -406,6 +406,7 @@
 				"source.cpp keyword.operator.new",
 				"source.cpp keyword.operator.delete",
 				"keyword.other.using",
+				"keyword.other.directive.using",
 				"keyword.other.operator"
 			],
 			"settings": {

extensions/theme-defaults/themes/hc_light.json

@@ -442,6 +442,7 @@
 				"source.cpp keyword.operator.new",
 				"source.cpp keyword.operator.delete",
 				"keyword.other.using",
+				"keyword.other.directive.using",
 				"keyword.other.operator",
 				"entity.name.operator"
 			],

extensions/theme-defaults/themes/light_plus.json

@@ -77,6 +77,7 @@
 				"source.cpp keyword.operator.new",
 				"source.cpp keyword.operator.delete",
 				"keyword.other.using",
+				"keyword.other.directive.using",
 				"keyword.other.operator",
 				"entity.name.operator"
 			],

extensions/theme-kimbie-dark/themes/kimbie-dark-color-theme.json

@@ -123,6 +123,7 @@
 				"keyword.operator.new.cpp",
 				"keyword.operator.delete.cpp",
 				"keyword.other.using",
+				"keyword.other.directive.using",
 				"keyword.other.operator"
 			],
 			"settings": {

extensions/theme-monokai-dimmed/themes/dimmed-monokai-color-theme.json

@@ -269,6 +269,7 @@
 				"keyword.operator.new.cpp",
 				"keyword.operator.delete.cpp",
 				"keyword.other.using",
+				"keyword.other.directive.using",
 				"keyword.other.operator"
 			],
 			"settings": {

extensions/vscode-colorize-tests/test/colorize-results/test_cs.json

@@ -3,14 +3,14 @@
 		"c": "using",
 		"t": "source.cs keyword.other.directive.using.cs",
 		"r": {
-			"dark_plus": "keyword: #569CD6",
-			"light_plus": "keyword: #0000FF",
+			"dark_plus": "keyword.other.directive.using: #C586C0",
+			"light_plus": "keyword.other.directive.using: #AF00DB",
 			"dark_vs": "keyword: #569CD6",
 			"light_vs": "keyword: #0000FF",
-			"hc_black": "keyword: #569CD6",
-			"dark_modern": "keyword: #569CD6",
-			"hc_light": "keyword: #0F4A85",
-			"light_modern": "keyword: #0000FF"
+			"hc_black": "keyword.other.directive.using: #C586C0",
+			"dark_modern": "keyword.other.directive.using: #C586C0",
+			"hc_light": "keyword.other.directive.using: #B5200D",
+			"light_modern": "keyword.other.directive.using: #AF00DB"
 		}
 	},
 	{