* lisp/macros.el (insert-kbd-macro): Recognize kmacros reliably

* lisp/macros.el (insert-kbd-macro): Recognize kmacros reliably

* lisp/macros.el (name-last-kbd-macro): Make it an alias of
kmacro-name-last-macro.
(insert-kbd-macro): Use kmacro-keyboard-macro-p so it also works for
kmacros that fail to have a `kmacro' property.
(see https://emacs.stackexchange.com/questions/37065, for an example).

* lisp/kmacro.el: Remove redundant :group args.
(kmacro-insert-counter): Simplify.
(kmacro-extract-lambda): Use car/cdr-safe.
(kmacro-p, kmacro-keyboard-macro-p): New functions.
(kmacro-name-last-macro): Use them.