Use metadata style in a few more places

Use metadata style in a few more places

I happened to find a few more spots that should use metadata style,
but do not.  I missed these in my earlier search somehow.  This patch
also adds gettext markup in a couple of spots where it was missing.

gdb/ChangeLog
2019-12-04  Tom Tromey  <tom@tromey.com>

	* valprint.c (val_print_string): Use metadata_style.
	* go-valprint.c (print_go_string): Use metadata style.
	* p-valprint.c (pascal_object_print_static_field): Use metadata
	style.
	* cp-valprint.c (cp_print_static_field): Use metadata style.

Change-Id: Id82ca2aa306c6694b111d5c92dfa6f0cce919ebf