- Tags are now created with `[tag]()`
- References are now created with `[tag]`
- Code spans are no longer wrapped

Fixes #27318

Problem:
`vim.lsp.util.rename()` deletes the buffers that are affected by
renaming. This has undesireable side effects. For example, when renaming
a directory, all buffers under that directory are deleted and windows
displaying those buffers are closed. Also, buffer options may change
after renaming.

Solution:
Rename the buffers with :saveas.

An alternative approach is to record all the relevant states and restore
it after renaming, but that seems to be more complex. In fact, the older
version was attempting to restore the states but only partially and
incorrectly.

Context:
Nvim catches errors from the user's `on_exit` and rpc handler callbacks
and prints the error message.

Problem:
Printing the error message uses Nvim api functions. But callbacks
mentioned above run in `:h lua-loop-callbacks` where most of `vim.api`
is not allowed, so Nvim itself raises error.

Solution:
`vim.schedule()` the error reporting when necessary.

feat(lsp): add fswatch watchfunc backend