bug#17569: 24.4.50; doc of "wrapper hooks"

[Glenn Morris]

Stefan Monnier wrote:

> Thanks, closing,

-- Variable: filter-buffer-substring-functions
     This variable is a wrapper hook (*note Running Hooks::), whose

-- Variable: abbrev-expand-functions
     This is a wrapper hook (*note Running Hooks::) run around the


Since you deleted the explanation of wrapper hooks, these xrefs are
pointless. Perhaps you want to delete the documentation of the obsolete
wrapper hooks too. (Though in general I don't understand why you delete
documentation of obsolete features, rather than simply adding a "The
following refers to an obsolete feature. In new code, use FOO" or
somesuch at the start.)

filter-buffer-substring-function, completion-in-region-function,
abbrev-expand-function don't seem to be documented. Only the obsolete
forms are documented.