Request improve `lsp-watch-root-folder`'s performance

[eval-exec]

      701877  85% - redisplay_internal (C function)
      502667  61%  - eval
      497271  60%   - tab-line-format
      497271  60%    - tab-line-tabs-window-buffers
      496872  60%     - seq-difference
      496872  60%      - seq-reduce
      496872  60%       - seq-do
      496872  60%        - mapc
      496574  60%         - lsp--server-register-capability
      496574  60%          - let*
      496574  60%           - if
      496574  60%            - progn
      496574  60%             - let*
      496574  60%              - let
      496574  60%               - while
      496574  60%                - let
      496574  60%                 - let*
      496284  60%                  - lsp-watch-root-folder
      496284  60%                   - let*
      494088  60%                    - lsp--all-watchable-directories
      494088  60%                     - let*
      494088  60%                      - if
      494088  60%                       - apply
      494088  60%                        - -map
      493095  59%                         - #<interpreted-function A46>
      493095  59%                          - lsp--all-watchable-directories
      492996  59%                           - let*
      492996  59%                            - if
      492996  59%                             - apply
      492996  59%                              - -map
      492898  59%                               - #<interpreted-function 2B9>
      492898  59%                                - lsp--all-watchable-directories
      492898  59%                                 - let*
      492707  59%                                  - if
      492611  59%                                   - apply
      492611  59%                                    - -map
      492611  59%                                     - #<interpreted-function 2B9>
      492611  59%                                      - lsp--all-watchable-directories
      428450  52%                                       - f-join
      428450  52%                                        - let
      428378  52%                                         - mapc
      428169  52%                                          - function
      428169  52%                                           - cconv-make-interpreted-closure
      427765  52%                                            - macroexpand-all
      427765  52%                                             - macroexp--expand-all
      427464  51%                                              - macroexp--all-forms
      427464  51%                                               - macroexp--expand-all
      427364  51%                                                - macroexp--expand-all
         872   0%                                                 - macroexp--all-clauses
         797   0%                                                  - macroexp--all-forms
         797   0%                                                   - macroexp--expand-all
         598   0%                                                    - #<byte-code-function 2D8>
         500   0%                                                     - macroexp--all-forms
         400   0%                                                      - macroexp--expand-all
         201   0%                                                         booleanp