fix: pick up new names when the name conflicts in 'introduce_named_generic'
Improve generation of names for generic parameters in `introduce_named_generics`.
fix#15731.
### Changes
- Modified `for_generic_parameter` function in `suggest_name.rs` to handle conflicts with existing generic parameters and generate unique names accordingly.
- Update `introduce_named_generic` function and pass existing params to `for_generic_parameter`, enabling the detection and handling of name collisions.
7040cef07d