Closes#35
Previously the treesitter javascript parser would treat `<></>`
specially and emit a `jsx_fragment`. We were checking for this type here
(from symbols-outline.nvim), though we did not include `jsx_fragment` in
the parse_ts function to even look for it.
jsx_fragment was recently removed from treesitter parser to reduce
complexity, so we will treat all jsx_element's without a `name` field in
`jsx_opening_element` as the shorthand fragment.
Using "Fragment" as the name in this case makes it look exactly the same
as if the user used `<Fragment></Fragment>` instead.
The check for `jsx_fragment` is still kept in case an older version of
the parser is still used, it can probably be removed next year.
Ref:
- tree-sitter/tree-sitter-javascript#227
