* switch the company-backend used by lsp-mode from company-lsp to
company-capf (said to provide better performance and allows us to remove
the dependency on company-lsp)
* when available (on recent builds of Emacs 27+), lsp-mode buffers will
now use a larger than default value of `read-process-output-max`.
According to the lsp-mode performance guide, this can also significantly
improve lsp-mode performance
* flycheck support recently moved into lsp proper; with this commit,
the lsp module follows suit and prefers lsp-flycheck over
lsp-ui-flycheck
* if the new module flag `+no-peek` is set, doom-emacs will now use the xref
backend for reference and definition lookup instead of the lsp-ui-peek-*
backend offered by lsp-ui-mode
