[clang] [clang-format] Limit how much work guessLanguage() can do (PR #78925)

[Owen Pan via cfe-commits]

owenca wrote:

> > @HighCommander4 I got a better idea. It seems that we don't need to add the parameter! See #82957. I think all you need to do is to call `getStyle()` with the default `""` for the `StringRef Code` argument to skip the Objective-C guesser.
> 
> Thanks. That does seem simpler, and seems like it should work just as well since the language guesser is the only thing that uses the `Code` argument.

I've merged #82957.

https://github.com/llvm/llvm-project/pull/78925