Improve documentation of 'repeat-mode' and related variables

Improve documentation of 'repeat-mode' and related variables

* lisp/bindings.el (next-error-repeat-map)
(page-navigation-repeat-map, undo-repeat-map):
* lisp/tab-bar.el (tab-bar-switch-repeat-map)
(tab-bar-move-repeat-map):
* lisp/window.el (other-window-repeat-map)
(resize-window-repeat-map): Mention repeatable commands in the doc
strings.
* lisp/repeat.el (repeat-exit-timeout, repeat-check-key)
(repeat-echo-function, repeat-mode, repeat-check-key)
(repeat-check-map, repeat-echo-message-string)
(repeat-echo-message, repeat-echo-mode-line)
(describe-repeat-maps): Improve wording of doc strings.
(describe-repeat-maps): Improve wording of the heading line.
(Bug#61183)

* doc/emacs/basic.texi (Repeating): Clarify and improve wording of
'repeat-mode' documentation.