Rollup merge of #144439 - xizheyin:symbol-rs, r=petrochenkov

Introduce ModernIdent type to unify macro 2.0 hygiene handling

This pr introduce ModernIdent type to unify macro 2.0 hygiene handling

1. Added ModernIdent type. Wraps Ident and automatically calls `normalize_to_macros_2_0()`
2. Unified identifier normalization. Replaced scattered ident.normalize_to_macros_2_0() calls with ModernIdent::new(ident)

r? ````@petrochenkov````

Author: Zalathar