This replaces the grow_cap function with the ensure_cap family of
functions, as they actually do what you want: You'll likely not want to
blindly increase the capacity of a growable, but you want to make sure that
the capacity is large enough to hold the elements you're about to insert.
- Simplify return types: Many functions that returned
`enum parse_fragment_result` only ever returned PF_OK or PF_ERROR.
Changing these functions to return bool simplifies things a lot. This
also helped in identifying some places where I didn't handle all
parse_fragment_result values properly.
- More cleaning up
- Allow linebreaks inside parenthesis
