Various minor variable/hook cleanups.

Various minor variable/hook cleanups.

* lisp/emacs-lisp/edebug.el (edebug-inhibit-emacs-lisp-mode-bindings):
Rename from gud-inhibit-global-bindings.

* lisp/emacs-lisp/eieio.el (eieio-pre-method-execution-hooks): Doc fix.

* lisp/erc/erc-dcc.el (erc-dcc-chat-filter-functions): Rename from
erc-dcc-chat-filter-hook, since this is an abnormal hook.

* lisp/nxml/nxml-glyph.el (nxml-glyph-set-functions): Rename abnormal
hook from nxml-glyph-set-hook.

* lisp/progmodes/cwarn.el (cwarn-mode): Remove redundant variable
declaration.

* lisp/progmodes/pascal.el (pascal-toggle-completions): Doc fix.

* lisp/textmodes/bibtex.el (bibtex-string-file-path, bibtex-file-path):
Convert to defcustom.

* lisp/url/url-handlers.el (url-handler-regexp):
* lisp/url/url-nfs.el (url-nfs-automounter-directory-spec):
* lisp/url/url-vars.el (url-load-hook): Convert to defcustom.