[flang-commits] [flang] [Flang] Add Sphinx man page support for Flang (PR #141882)

[Samarth Narang via flang-commits]

snarang181 wrote:

@kiranchandramohan @tarunprabhu, what do you guys think about modifying `index.md` in the following manner ?  This will load things on demand and we should not be hitting the `nonexistent document` errors. 

```
```{eval}
import os
if os.path.exists('FlangCommandLineReference.rst'):
    print('FlangCommandLineReference')
```

https://github.com/llvm/llvm-project/pull/141882