Auto merge of #113476 - fee1-dead-contrib:c-str-lit, r=petrochenkov

Reimplement C-str literals

This reverts #113334, cc `@fmease.`

While converting lexer tokens to ast Tokens in `rustc_parse`, we check the edition of the span of the token. If the edition < 2021, we split the token into two, one being the identifier and other being the str literal.

Author: bors