Fix typos and remove superfluous backslash-quoting in htmlfontify.el.

Fix typos and remove superfluous backslash-quoting in htmlfontify.el.

* htmlfontify.el (htmlfontify-load-rgb-file)
  (htmlfontify-unload-rgb-file, hfy-fallback-colour-values)
  (htmlfontify-manual, htmlfontify, hfy-page-header, hfy-page-footer)
  (hfy-src-doc-link-style, hfy-src-doc-link-unstyle, hfy-link-extn)
  (hfy-link-style-fun, hfy-index-file, hfy-instance-file)
  (hfy-html-quote-regex, hfy-init-kludge-hook, hfy-post-html-hooks)
  (hfy-default-face-def, hfy-etag-regex, hfy-html-quote-map)
  (hfy-etags-cmd-alist-default, hfy-etags-bin, hfy-ignored-properties)
  (hfy-which-etags, hfy-etags-cmd, hfy-istext-command, hfy-display-class)
  (hfy-optimisations, hfy-tags-cache, hfy-tags-sortl, hfy-tags-rmap)
  (hfy-style-assoc, hfy-sheet-assoc, hfy-facemap-assoc, hfy-interq)
  (hfy-colour-vals, hfy-default-header, hfy-link-style-string)
  (hfy-triplet, hfy-slant, hfy-weight, hfy-combined-face-spec)
  (hfy-face-attr-for-class, hfy-face-to-style-i, hfy-size-to-int)
  (hfy-flatten-style, hfy-face-to-style, hfy-face-or-def-to-name)
  (hfy-face-to-css, hfy-p-to-face, hfy-p-to-face-lennart, hfy-face-at)
  (hfy-fontified-p, hfy-merge-adjacent-spans, hfy-buffer)
  (hfy-html-enkludge-buffer, hfy-html-quote, hfy-html-dekludge-buffer)
  (hfy-force-fontification, htmlfontify-buffer, hfy-dirname)
  (hfy-make-directory, hfy-text-p, hfy-mark-tag-names, hfy-relstub)
  (hfy-href-stub, hfy-href, hfy-mark-tag-hrefs, hfy-prepare-index-i)
  (hfy-prepare-index, hfy-prepare-tag-map, hfy-subtract-maps)
  (htmlfontify-run-etags): Fix typos in docstrings and remove superfluous
  backslash-quoting from parentheses, etc.