Improve documentation of 'edit-abbrevs-mode'

* lisp/abbrev.el (edit-abbrevs-mode): Refer to 'edit-abbrevs'
for more detailed usage information.  (Bug#33443)
(edit-abbrevs): Doc fix.

lisp/abbrev.el

@@ -150,11 +150,12 @@ Otherwise display all abbrevs."
 (defun edit-abbrevs ()
   "Alter abbrev definitions by editing a list of them.
 Selects a buffer containing a list of abbrev definitions with
-point located in the abbrev table of current buffer.
+point located in the abbrev table for the current buffer, and
+turns on `edit-abbrevs-mode' in that buffer.
 You can edit them and type \\<edit-abbrevs-map>\\[edit-abbrevs-redefine] to redefine abbrevs
 according to your editing.
-Buffer contains a header line for each abbrev table,
- which is the abbrev table name in parentheses.
+The abbrevs editing buffer contains a header line for each
+abbrev table, which is the abbrev table name in parentheses.
 This is followed by one line per abbrev in that table:
 NAME   USECOUNT   EXPANSION   HOOK
 where NAME and EXPANSION are strings with quotes,
@@ -1022,7 +1023,9 @@ SORTFUN is passed to `sort' to change the default ordering."
 ;; Keep it after define-abbrev-table, since define-derived-mode uses
 ;; define-abbrev-table.
 (define-derived-mode edit-abbrevs-mode fundamental-mode "Edit-Abbrevs"
-  "Major mode for editing the list of abbrev definitions.")
+  "Major mode for editing the list of abbrev definitions.
+This mode is for editing abbrevs in a buffer prepared by `edit-abbrevs',
+which see.")
 
 (provide 'abbrev)