muse-colors: Separate highlighting rules according to major mode.

muse-colors: Separate highlighting rules according to major mode.

* lisp/muse-colors.el (muse-colors-regexp, muse-colors-vector): Remove.
  (muse-colors-highlighting-registry)
  (muse-colors-make-highlighting-struct)
  (muse-colors-highlighting.regexp, muse-colors-highlighting.vector)
  (muse-colors-highlighting.remaining, muse-colors-highlighting-entry)
  (muse-colors-find-highlighting, muse-colors-define-highlighting): New
  scheme for separating highlighting rules according to major-mode.
  (muse-configure-highlighting, muse-use-font-lock): Use
  muse-colors-define-highlighting.
  (muse-colors-region): Permit the vector to contain more than one rule.
  Handle case where we have rules that are not in the vector and do not
  have the same function handler.  Make sure that the match data exactly
  corresponds to the regexp that goes with the rule.
  (muse-colors-custom-tags, muse-colors-explicit-link): No need to
  explicitly call `looking-at', because the match data will be correct.
  (muse-colors-implicit-link): Use match-string 0 instead of match-string
  1, now that the match data is accurate.

* lisp/muse-wiki.el (muse-wiki-update-project-file-regexp)
  (muse-wiki-wikiword-regexp): Call muse-colors-define-highlighting.
  (muse-wiki-update-interwiki-regexp): Only update the highlighting if
  the value has changed.