Cannot search symbols @ and ! in ^R search mode (--use-backslash not affects)

[telychko]

$ less --version
less 643 (PCRE2 regular expressions)

Cannot search @ and ! symbols in non-regexp mode:

less '+/^R@' file
It's ok as @ is the one of the search mode, but would be good that special symbols could be available via --use-backslash option.

Suggested solution:
less --use-backslash '+/^R@' file

^R there is the one raw symbol.

[gwsw]

In 16a5260 and later you can use the new ctrl-L search modifier to search for a search modifier character:

less '+/^R^L@' file

[telychko]

Thank you for your great work!