mu4e: Use mu4e-query-rewrite-function

The (new) mu4e-search-query-rewrite-function is a bit too long, let's keep the
old one.

mu4e/mu4e-headers.el

@@ -796,7 +796,7 @@ Switch to the output buffer for the results. If IGNORE-HISTORY is
 true, do *not* update the query history stack."
   (let* ((buf (get-buffer-create mu4e-headers-buffer-name))
          (inhibit-read-only t)
-         (rewritten-expr (funcall mu4e-search-query-rewrite-function expr))
+         (rewritten-expr (funcall mu4e-query-rewrite-function expr))
          (maxnum (unless mu4e-search-full mu4e-search-results-limit)))
     (with-current-buffer buf
       (mu4e-headers-mode)

mu4e/mu4e-main.el

@@ -173,7 +173,7 @@ clicked."
            for bm in bmks
            for key = (string (plist-get bm :key))
            for name = (plist-get bm :name)
-           for query = (funcall (or mu4e-search-query-rewrite-function #'identity)
+           for query = (funcall (or mu4e-query-rewrite-function #'identity)
                                 (plist-get bm :query))
            for qcounts = (and (stringp query)
                               (cl-loop for q in queries

mu4e/mu4e-search.el

@@ -62,10 +62,7 @@ If this is nil, search for up to `mu4e-search-results-limit')")
 (defvar mu4e-search-threads t
   "Whether to calculate threads for the search results.")
 
-
-(define-obsolete-variable-alias 'mu4e-query-rewrite-function
-  'mu4e-search-query-rewrite-function "1.7.0")
-(defcustom mu4e-search-query-rewrite-function 'identity
+(defcustom mu4e-query-rewrite-function 'identity
   "Function to rewrite a query.
 
 It takes a search expression string, and returns a possibly
@@ -87,7 +84,6 @@ anything about the query, it just does text replacement."
   :type 'function
   :group 'mu4e-search)
 
-
 (define-obsolete-variable-alias
   'mu4e-headers-search-bookmark-hook
   'mu4e-search-bookmark-hook "1.7.0")