Miscellaneous checkdoc fixes

Miscellaneous checkdoc fixes

* lisp/ansi-color.el (ansi-color--ensure-context):
* lisp/doc-view.el (doc-view-svg-face):
* lisp/external-completion.el (external-completion-table):
* lisp/ffap.el (ffap-ro-mode-hook, ffap-gnus-hook):
* lisp/find-file.el:
* lisp/flow-ctrl.el (flow-control-c-s-replacement)
(flow-control-c-q-replacement):
* lisp/forms.el (forms-multi-line):
* lisp/help.el (search-forward-help-for-help):
* lisp/hi-lock.el (hi-lock-use-overlays):
* lisp/image.el (find-image):
* lisp/isearch.el (isearch-forward, isearch-forward-regexp)
(isearch-lazy-count-format):
* lisp/jsonrpc.el (jsonrpc--continue, initialize-instance):
* lisp/mouse-copy.el (mouse-kill-preserving-secondary):
* lisp/pixel-scroll.el (pixel-bob-at-top-p)
(pixel-scroll-down-and-set-window-vscroll):
* lisp/printing.el (pr-gv-command, pr-gs-command)
(pr-gs-switches):
* lisp/register.el (register-use-preview):
* lisp/repeat.el (repeat-check-key):
* lisp/saveplace.el (save-place-abbreviate-file-names):
* lisp/select.el (gui--clipboard-selection-unchanged-p):
* lisp/ses.el (ses-header-row):
* lisp/simple.el (transpose-sexps-default-function)
(normal-erase-is-backspace, normal-erase-is-backspace-mode):
* lisp/sqlite-mode.el (sqlite-mode):
* lisp/tempo.el (tempo-insert-region):
* lisp/term.el (term-mode-map, term-mode, term-char-mode):
Checkdoc fixes.

(cherry picked from commit e4760109ac8e3b0d73dd37e11121a01362542364)