selectrum: improve ivy parity

- add `completion-at-point` as analogue to `cousnel-company`
- fix emacs-bindings `counsel-company` binding to respect helm and selectrum
- add org jump commands `consult-org-heading` and `consult-org-agenda` bindings
- add `consult-history` as `counsel-minibuffer-history` analogue
- add support for `doom/help-search`
- update TODO.org

core/autoload/help.el

@@ -226,6 +226,8 @@ will be automatically appended to the result."
                   #'+ivy-file-search)
                  ((fboundp '+helm-file-search)
                   #'+helm-file-search)
+                 ((fboundp '+selectrum-file-search)
+                  #'+selectrum-file-search)
                  ((rgrep
                    (read-regexp
                     "Search for" (or initial-input 'grep-tag-default)