languages: go.mod/go.work fix highlighting no longer working (#7705)

At some point go.mod and go.work syntax highlighting quit working. Looks
like the grammars weren't matching for some reason and I'm not sure how
they were working originally.

Not sure if we could write a test to make sure the tree-sitter queries
are being loaded for the grammars or not but seems like something that
could be useful to avoid something like this in the future.

crates/zed/src/languages/gomod/config.toml

@@ -1,5 +1,5 @@
 name = "Go Mod"
-grammar = "go"
+grammar = "gomod"
 path_suffixes = ["mod"]
 line_comments = ["//"]
 autoclose_before = ")"

crates/zed/src/languages/gowork/config.toml

@@ -1,5 +1,5 @@
 name = "Go Work"
-grammar = "go_work"
+grammar = "gowork"
 path_suffixes = ["work"]
 line_comments = ["//"]
 autoclose_before = ")"