[clang] [flang] [flang][driver] Add pre-processing type to `.i` files (PR #104664)

[Andrzej Warzyński via cfe-commits]

banach-space wrote:

Hi Kareem, thanks for the fix! Is there any reference that would document .i files? Perhaps GFortran docs? This might be sth standard, but we should capture that in our docs nonetheless (eg in a commit summary).


Btw, I will be OOO for a while, so apologies in advance if there's a delay from my side.

https://github.com/llvm/llvm-project/pull/104664