Fix describe-function keybinding confusion

* lisp/help-fns.el (describe-function-1): Compute signature
in the original buffer, not in standard-output, so that
substitute-command-keys uses the proper keybindings.
This fixes Bug#21412, introduced in commit
2015-06-11T10:23:46-0700!eggert@cs.ucla.edu.

diff --git a/lisp/help-fns.el b/lisp/help-fns.el
index a1d121c457fd896b8f02e33e5e77ca3e9fff3c67..f5c7eb30c8c9f38d5d0b1f03f1356e11d388b475 100644 (file)
--- a/lisp/help-fns.el
+++ b/lisp/help-fns.el
@@ -614,9 +614,9 @@ FILE is the file where FUNCTION was probably defined."
             (autoload-do-load real-def))
 
         (help-fns--key-bindings function)
-        (with-current-buffer standard-output
-         (let ((doc (help-fns--signature function doc-raw sig-key
-                                          real-function nil)))
+        (let ((doc (help-fns--signature function doc-raw sig-key
+                                        real-function nil)))
+          (with-current-buffer standard-output
            (run-hook-with-args 'help-fns-describe-function-functions function)
            (insert "\n"
                    (or doc "Not documented."))))))))