[clang-tools-extra] Enforce SL.con.3: Add check to replace operator[] with at() (PR #90043)

[Congcong Cai via cfe-commits]

HerrCai0907 wrote:

> To be clear and reiterate my previous comment: this check should NOT require users to use at(). That behavior should be opt-in. It should only warn about using operator[]. It's up to the users to figure out what the best replacement is.

I don't think it is a good solution. For this kind of projects, they should disable this check directly.

Maybe it is optimization to disable this check if exception feature is disabled.

https://github.com/llvm/llvm-project/pull/90043