package.json: reuse go.mod tmGrammar for go.work syntax highlight

This handles syntax highlighting in VS Code Go when
users don't opt in for semantic tokens to be implemented
in golang/go#50930.

The go.mod and go.work syntaxes are currently identical except
the keywords.

Change-Id: I9395588c9291f88ed2690e939bf486f626e12a4c
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/390594
Trust: Hyang-Ah Hana Kim <[email protected]>
Run-TryBot: Hyang-Ah Hana Kim <[email protected]>
TryBot-Result: kokoro <[email protected]>
Reviewed-by: Michael Matloob <[email protected]>
Reviewed-by: Peter Weinberger <[email protected]>

Author: hyangah

package.json

@@ -179,6 +179,11 @@
         "scopeName": "go.mod",
         "path": "./syntaxes/go.mod.tmGrammar.json"
       },
+      {
+        "language": "go.work",
+        "scopeName": "go.mod",
+        "path": "./syntaxes/go.mod.tmGrammar.json"
+      },
       {
         "language": "go.sum",
         "scopeName": "go.sum",