Fix formatting of conditionals

[tfausak]

As discovered in #40.

-- before
if p
  t

else
  f

-- after
if p
  t
else
  f

I generally want to avoid special-casing things, but conditionals feel like a reasonable exception. The else conceptually belongs to the if above it. Separating them by an extra space makes things more confusing.

[tfausak]

https://cabal.readthedocs.io/en/3.10/cabal-package.html#conditional-blocks

As far as I know this is the only special syntax. I already have special cases in place for conditional arguments here:

cabal-gild/source/library/CabalGild/Action/Render.hs

Lines 117 to 119 in ffc0b4d

	bs /= ByteString.singleton 0x21 -- !
	&& bs /= ByteString.singleton 0x28 -- (
	&& bs /= ByteString.singleton 0x29 -- )