users_guide: fix sphinx error caused by non-explicit override
authorZejun Wu <watashi@watashi.ws>
Thu, 20 Sep 2018 20:05:28 +0000 (16:05 -0400)
committerBen Gamari <ben@smart-cactus.org>
Thu, 20 Sep 2018 20:06:01 +0000 (16:06 -0400)
commit5ed9c86134200db615908d445702522d95f9025a
tree553d0add8140968c66ac4ef555dd05dcd9e4bf50
parent6f717bc6440d6dcf368fc605fabb86d7619510af
users_guide: fix sphinx error caused by non-explicit override

Encouter following error when `make`:

```
Extension error:
The 'ghc-flag' directive is already registered to domain std
```

as we register `ghc-flag` to `std` in `add_object_type` first and then
overtride it in `add_directive_to_domain`.

Test Plan:
  make -C utils/haddock/doc html SPHINX_BUILD=/usr/bin/sphinx-build

Reviewers: austin, bgamari, patrickdoc

Subscribers: rwbarton, carter

Differential Revision: https://phabricator.haskell.org/D5161

(cherry picked from commit 8c7d33a8ff6d3ea55b5dc8108d9441521af68ab8)
docs/users_guide/flags.py