The task is to use the new tokens emitted by the lexer (#7042) and create the ExprFString node using it. This will require major refactor in string.rs to support this.

Relevant PRs:

• Add support for parsing f-string as per PEP 701 #7041
• Use narrow type for string parsing patterns #7211
• Disallow non-parenthesized lambda expr in f-string #7263
• Fix curly brace escape handling in f-strings #7331
• Allow NUL character in f-strings #7378