Add new face 'help-key-binding' for keybindings in help

* lisp/faces.el (help-key-binding): New face.
* lisp/help.el
(help-for-help): Rename from 'help-for-help-internal'.  Use
'substitute-command-keys' syntax.
(help): Make into alias for 'help-for-help'.
(help-for-help-internal): Make into obsolete alias for
'help-for-help'.
(help--key-description-fontified): New function to add the
'help-key-binding' face.
(help-key-description, substitute-command-keys)
(describe-map-tree, help--describe-command)
(help--describe-translation, describe-map):
* lisp/help-fns.el (help-fns--key-bindings, describe-mode):
Use above new function.
* lisp/isearch.el (isearch-help-for-help-internal): Use
`substitute-command-keys' syntax.
* lisp/help-macro.el (make-help-screen): Use
'substitute-command-keys' and 'help--key-description-fontified'.
Simplify.
* src/keymap.c (describe_key_maybe_fontify): New function to add
the 'help-key-binding' face to keybindings.
(describe_vector): Use above new keybinding.
(syms_of_keymap) <Qfont_lock_face, Qhelp_key_binding>: New
DEFSYMs.
(fontify_key_properties): New static variable.
* lisp/tooltip.el (tooltip-show): Avoid overriding faces in
specified tooltip text.
* test/lisp/help-tests.el (with-substitute-command-keys-test):
Don't test for text properties.
(help-tests-substitute-command-keys/add-key-face)
(help-tests-substitute-command-keys/add-key-face-listing):
New tests.

1 files changed, 23 insertions, 2 deletions

diff --git a/src/keymap.c b/src/keymap.c
index 782931fadff..bb26b6389d4 100644
--- a/src/keymap.c
+++ b/src/keymap.c
@@ -2846,6 +2846,21 @@ DESCRIBER is the output function used; nil means use `princ'.  */)
   return unbind_to (count, Qnil);
 }
 
+static Lisp_Object fontify_key_properties;
+
+static Lisp_Object
+describe_key_maybe_fontify (Lisp_Object str, Lisp_Object prefix,
+                                   bool keymap_p)
+{
+  Lisp_Object key_desc = Fkey_description (str, prefix);
+  if (keymap_p)
+    Fadd_text_properties (make_fixnum (0),
+                          make_fixnum (SCHARS (key_desc)),
+                          fontify_key_properties,
+                          key_desc);
+  return key_desc;
+}
+
 DEFUN ("help--describe-vector", Fhelp__describe_vector, Shelp__describe_vector, 7, 7, 0,
        doc: /* Insert in the current buffer a description of the contents of VECTOR.
 Call DESCRIBER to insert the description of one value found in VECTOR.
@@ -3021,7 +3036,7 @@ describe_vector (Lisp_Object vector, Lisp_Object prefix, Lisp_Object args,
       if (!NILP (elt_prefix))
         insert1 (elt_prefix);
 
-      insert1 (Fkey_description (kludge, prefix));
+      insert1 (describe_key_maybe_fontify (kludge, prefix, keymap_p));
 
       /* Find all consecutive characters or rows that have the same
          definition.  But, if VECTOR is a char-table, we had better
@@ -3071,7 +3086,7 @@ describe_vector (Lisp_Object vector, Lisp_Object prefix, Lisp_Object args,
           if (!NILP (elt_prefix))
             insert1 (elt_prefix);
 
-          insert1 (Fkey_description (kludge, prefix));
+          insert1 (describe_key_maybe_fontify (kludge, prefix, keymap_p));
         }
 
       /* Print a description of the definition of this character.
@@ -3200,6 +3215,12 @@ be preferred.  */);
   staticpro (&where_is_cache);
   staticpro (&where_is_cache_keymaps);
 
+  DEFSYM (Qfont_lock_face, "font-lock-face");
+  DEFSYM (Qhelp_key_binding, "help-key-binding");
+  staticpro (&fontify_key_properties);
+  fontify_key_properties = Fcons (Qfont_lock_face,
+                                  Fcons (Qhelp_key_binding, Qnil));
+
   defsubr (&Skeymapp);
   defsubr (&Skeymap_parent);
   defsubr (&Skeymap_prompt);