go/types: fix typo in Info.Types doc comment

Change-Id: Ib95b77ab3dc6e48158e25e70fabb2579f3706b5f
Reviewed-on: https://go-review.googlesource.com/c/go/+/669755
Auto-Submit: Russ Cox <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Robert Griesemer <[email protected]>

Author: rsc

src/go/types/api.go

@@ -228,7 +228,7 @@ type Info struct {
 	// Similarly, no type is recorded for the (synthetic) FuncType
 	// node in a FuncDecl.Type field, since there is no corresponding
 	// syntactic function type expression in the source in this case
-	// Instead, the function type is found in the Defs.map entry for
+	// Instead, the function type is found in the Defs map entry for
 	// the corresponding function declaration.
 	Types map[ast.Expr]TypeAndValue