d: Merge upstream dmd 108ca1bcd.

d: Merge upstream dmd 108ca1bcd.

Renames OutBuffer::peekString to OutBuffer::peekChars, and
OutBuffer::extractString to OutBuffer::extractChars.  All callers have
been updated as appropriate.

Reviewed-on: https://github.com/dlang/dmd/pull/11247

gcc/d/ChangeLog:

	* dmd/MERGE: Merge upstream dmd 108ca1bcd.
	* d-diagnostic.cc (expand_d_format): Adjust to use extractChars().
	* d-frontend.cc (Loc::toChars): Likewise.
	* d-lang.cc (deps_write): Likewise.
	(d_parse_file): Likewise.
	* decl.cc (d_mangle_decl): Likewise.
	* intrinsics.cc (maybe_set_intrinsic): Likewise.