gopls/internal/golang: check the comment range before emiting semantic tokens

Change-Id: If300720c92bfb1ac63b395efc2419f1f1c8bed8f
Reviewed-on: https://go-review.googlesource.com/c/tools/+/580595
Reviewed-by: Alan Donovan <[email protected]>
Auto-Submit: Alan Donovan <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Robert Findley <[email protected]>

Author: rogeryk

gopls/internal/golang/semtok.go

@@ -142,6 +142,10 @@ func (tv *tokenVisitor) visit() {
 
 	for _, cg := range f.Comments {
 		for _, c := range cg.List {
+			// Only look at the comment that overlap the range.
+			if c.End() <= tv.start || c.Pos() >= tv.end {
+				continue
+			}
 			tv.comment(c, importByName)
 		}
 	}