* Add treesitter textobject queries
Only for Go, Python and Rust for now.
* Add tree-sitter textobjects
Only has functions and class objects as of now.
* Fix tests
* Add docs for tree-sitter textobjects
* Add guide for creating new textobject queries
* Add parameter textobject
Only parameter.inside is implemented now, parameter.around
will probably require custom predicates akin to nvim' `make-range`
since we want to select a trailing comma too (a comma will be
an anonymous node and matching against them doesn't work similar
to named nodes)
* Simplify TextObject cell init
