gopls/internal/golang: fix bug browsing assembly for (T).f methods

This change fixes a bug in the logic to construct symbol names
that match those produced by the compiler: nonpointer methods
should be "T.f" not "(T).f".

Tested interactively.

Fixes golang/go#70888

Change-Id: I2a9d68fffbc75cb9f3719b58968ca1297bcbd3cf
Reviewed-on: https://go-review.googlesource.com/c/tools/+/637255
Reviewed-by: Robert Findley <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Auto-Submit: Alan Donovan <[email protected]>

Author: adonovan

gopls/internal/golang/codeaction.go

@@ -815,12 +815,12 @@ func goAssembly(ctx context.Context, req *codeActionsRequest) error {
 				sym.WriteString(".")
 				if sig.Recv() != nil {
 					if isPtr, named := typesinternal.ReceiverNamed(sig.Recv()); named != nil {
-						sym.WriteString("(")
 						if isPtr {
-							sym.WriteString("*")
+							fmt.Fprintf(&sym, "(*%s)", named.Obj().Name())
+						} else {
+							sym.WriteString(named.Obj().Name())
 						}
-						sym.WriteString(named.Obj().Name())
-						sym.WriteString(").")
+						sym.WriteByte('.')
 					}
 				}
 				sym.WriteString(fn.Name())