clarify behavior single quote regexps

The documentation was ambiguous about what type of interpolation
was disabled in single quote regexps. It is a bit debateable whether
"\n" in a regex is a regexp meta-escapes which happens to match "\n",
or if it is a string escape that needs to be interpolated. Since single
quote regexps should allow regexp meta-escapes (for instance \s), then
it makes more sense to treat \n and \x{..} also as regexp meta-escapes,
which then leaves nothing but variables that /could/ be interpolated.

This effectively officially defines the current behavior as correct,
and will allow us to close a number of tickets because of it. In
particular we can close #21491 as "not a bug", and probably also related
tickets.

0 files changed, 0 insertions, 0 deletions