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

[via cfe-commits]

Sirraide wrote:

> I will try to do single commits and later squash them!

You don’t even need to squash them yourself; Github does that automatically because we use ‘squash and merge’.

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