This fixes issues where subsequent calls to vim.lsp.codelens.refresh()
would have no effect due to the buffer not getting cleared from the
active_refresh table.

Examples of how such scenarios would occur are:
  - A textDocument/codeLens result yielded an error.
  - The 'textDocument/codeLens' handler was overriden in such a way that
    it no longer called vim.lsp.codelens.on_codelens().

It looks a bit off with the extmark going over the cursorline.

(With hl_mode combine it keeps the background of the cursorline under the codelens virtualtext)

Co-authored-by: Michael Lingelbach <m.j.lbach@gmail.com> Mathias Fußenegger <mfussenegger@users.noreply.github.com>

Also adds a check against the server capabilities to fix
https://github.com/neovim/neovim/issues/15183

Follow up to https://github.com/neovim/neovim/pull/15504

feat(lsp)!: change handler signature

Previously, the handler signature was:

  function(err, method, params, client_id, bufnr, config)

In order to better support external plugins that wish to extend the
protocol, there is other information which would be advantageous to
forward to the client, such as the original params of the request that
generated the callback.

In order to do this, we would need to break symmetry of the handlers, to
add an additional "params" as the 7th argument.

Instead, this PR changes the signature of the handlers to:

  function(err, result, ctx, config)

where ctx (the context) includes params, client_id, and bufnr. This also leaves
flexibility for future use-cases.

BREAKING_CHANGE: changes the signature of the built-in client handlers, requiring
updating handler calls