[flang-commits] [clang] [flang] [flang][docs] Update the `-Ofast` description in `FlangDriver.md` (PR #180138)

[Shunsuke Watanabe via flang-commits]

s-watanabe314 wrote:

@kiranchandramohan  I updated the help text for the driver option.

https://github.com/llvm/llvm-project/pull/180138