Hi Wilhelm,

Currently I'm adding the new 'list' thing to all ts-modes
and noticed that elixir-ts-mode defines the function
'elixir-ts--forward-sexp'.

This function can be superseded by the 'list' definition
in treesit-thing-settings that supports such commands
as 'forward-sexp', 'forward-list', 'up-list', 'down-list',
and modes 'show-paren-mode', 'hs-minor-mode'.

I have tested all cases, and this patch covers all list nodes.
The only doubtful case is the commented out definition

  ;; (and "\\`call\\'" ,#'elixir-ts--defun-p)

When enabled, it causes too much trouble
with e.g. 'show-paren-mode', etc.
OTOH, this definition is not much needed since
'C-M-a' (beginning-of-defun) and 'C-M-e' (end-of-defun)
already cover this need instead of using 'C-M-f/b',
so 'C-M-a/e' could be used to navigate between functions.
And 'C-M-f/b' navigate in all other cases such as
between 'do' and 'end', parens, etc.