Add new sphinx domain for Haka
Fix xref issue with Haka domain
Change sphinx module description in haka domain
Improve haka domain

Add () in index for haka functions to behave as the previous Lua domain.
Remove unused haka.grammar.re
Update grammar documentation
Improve grammar option documentation
Fix xref issue with haka domain
Add missing return value documentation
Update regexp documentation
Improve haka domain xref
Indent class fields
Fix html style issue
Improve haka domain

Simplify the haka domain to avoid make an explicit difference between
function/method and data/attribute.
Update grammar documentation
Update the log and alert documentation

Split the loog and alert doc in two separated files.
Improve haka domain

Add operator description. Add readonly attribute option.
Add readonly option on attributes
Fix whitespaces
Update vbuffer documentation