[clang] [clang] Fix-it hint for `++this` -> `++*this` when deref is modifiable (PR #94159)

[Rajveer Singh Bharadwaj via cfe-commits]

Rajveer100 wrote:

@Sirraide 
Let me know if any further changes are needed. All tests should pass once CI finishes.

https://github.com/llvm/llvm-project/pull/94159