[torque] Update vscode extension to reflect recent changes

This CL adds 'typeswitch' and 'case' as a keyword and removes some
unused ones. It also adds 'UncheckedCast', 'Cast', 'Convert' and
'FromConstexpr' as support functions.

Bug: v8:7793
Change-Id: Ia58045a5fb0f599c7c17cbf11d4e60ed55db7334
Reviewed-on: https://chromium-review.googlesource.com/1219389Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Simon Zünd <szuend@google.com>
Cr-Commit-Position: refs/heads/master@{#55850}

tools/torque/vscode-torque/syntaxes/torque.tmLanguage.json

@@ -30,7 +30,7 @@
 		},
 		{
 			"name": "support.function.torque",
-			"match": "\\b(min|max|assert|check|debug|unreachable)\\b"
+			"match": "\\b(assert|check|debug|unreachable|Cast|Convert|FromConstexpr|UnsafeCast)\\b"
 		},
     {
       "name": "support.variable.torque",
@@ -65,7 +65,7 @@
 			},
 			{
 				"name": "keyword.other.torque",
-				"match": "\\b(constexpr|module|macro|builtin|runtime|javascript|implicit|deferred|cast|convert|label|labels|tail|isnt|is|let|generates|type|extends|extern|const)\\b"
+				"match": "\\b(constexpr|module|macro|builtin|runtime|javascript|implicit|deferred|label|labels|tail|let|generates|type|extends|extern|const|typeswitch|case)\\b"
 			},
 			{
 				"name": "keyword.operator.torque",