cmd/compile/internal/syntax: correct an error string
When we have an error in a function type used in an expression
we don't know until we see an opening { whether we have a function
literal or a function type. Use "function type" as context because
that's always correct in the specific error message.
Change-Id: I9aad8fcddf31ae53daa53cebd2c2001f08eabde0
Reviewed-on: https://go-review.googlesource.com/c/go/+/401316 Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Robert Griesemer <gri@google.com> Reviewed-by: Robert Griesemer <gri@google.com>