Adds Go raw string literals per Go spec § String literals:
backtick-delimited, no escape processing, may span multiple
lines, '\r' chars discarded from the value.
gl-read-raw-string! mirrors gl-read-string! but skips escape
handling and the \r filter. scan! routes the leading backtick
to it; emits "string" type (same as interpreted strings — no
need to distinguish at parse/type time).
lex 123/123.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
giles
65467c232b