Also add a few missing docstrings.
* lisp/emacs-lisp/elisp-scope.el (elisp-scope-symbol-role-p)
(elisp-scope-read-symbol-role, elisp-scope-special-variables)
(elisp-scope-let, elisp-scope-let*): Add docstring.
(elisp-scope-counter, elisp-scope-callback)
(elisp-scope-current-let-alist-form, elisp-scope-local-new)
(elisp-scope-sym-pos, elisp-scope-sym-bare)
(elisp-scope-report, elisp-scope-special-variable-p)
(elisp-scope-let-1, elisp-scope-variable)
(elisp-scope-binding, elisp-scope-symbol): Rename, replace
'elisp-scope-' prefix with 'elisp-scope--' to indicate that
these are private. Update all references.