1. Unset ccls-sem-highlight-method if lsp-enable-semantic-highlighting
is nil (perhaps this should be reported upstream).
2. Fix load-order. Take `(use-package X :after Y :config Z)` for
example. Z will be evaluated after Y loads, not after X loads. To
customize Z you'd need to do `(after! Y ...)`. This is
counter-intuitive. By removing `:after Y` and explicitly loading X
when Y loads in :init, you can customize Z with `(after! X ...)` again.
3. Tie ccls-code-lens-mode to lsp-lens-mode, so lsp-lens-enable is
respected.