internal/lsp/source: rename uses of embedded fields

When renaming a type name, also rename indirect uses of the name as an
embedded field. This is conservatively isolated to just renames for now;
it's not clear to me that users would also want to see uses of embedded
fields as references.

Fixes golang/go#43616

Change-Id: I41913d037fedb8c27a448cd922eeaf11a02d01f1
Reviewed-on: https://go-review.googlesource.com/c/tools/+/282932
Run-TryBot: Robert Findley <rfindley@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
Trust: Robert Findley <rfindley@google.com>
diff --git a/internal/lsp/source/rename.go b/internal/lsp/source/rename.go
index 26c705a..fdf3f63 100644
--- a/internal/lsp/source/rename.go
+++ b/internal/lsp/source/rename.go
@@ -91,7 +91,7 @@
 	if pkg == nil || pkg.IsIllTyped() {
 		return nil, errors.Errorf("package for %s is ill typed", f.URI())
 	}
-	refs, err := references(ctx, s, qos, true, false)
+	refs, err := references(ctx, s, qos, true, false, true)
 	if err != nil {
 		return nil, err
 	}