bugfix @see tag does not work with static function/member

[xsjad0]

Using JSDocs @see tag to reference a static function/member causes Sphinx to crash with the following error message

Since we've added the directive js:staticfunction we also have to specify a new object type within the JS Domain that allows Sphinx to resolve the any reference.

This example code works now:

    /**
     * SomeMembers
     */
    class SomeMembers {
        /**
        * Some static member.
        *
        * @returns {void}
        */
        static someStaticMember() {
            // No use of this
        }

        /**
        * Non-static member
        *
        * @see someStaticMember
        * @returns {void}
        */
        nonStaticMember() {
            this.nonStatic = true;
        }
    }

It's also possible to reference a static function/member by using the js:func: role

    :js:func:`SomeMembers.someStaticMember`

Unfortunately, there is no way extend Sphinx to define the correct index text for static functions.

See sphinx.domains.javascript.py code snippet

def get_index_text(self, objectname: str, name_obj: Tuple[str, str]) -> str:
    name, obj = name_obj
    if self.objtype == 'function':
        if not obj:
            return _('%s() (built-in function)') % name
        return _('%s() (%s method)') % (name, obj)
    elif self.objtype == 'class':
        return _('%s() (class)') % name
    elif self.objtype == 'data':
        return _('%s (global variable or constant)') % name
    elif self.objtype == 'attribute':
        return _('%s (%s attribute)') % (name, obj)
    return ''

Unless we generate a JS index, we may not notice any restriction...
What do you think??

[willkg]

I redid the suggested fix in #217 after going through and making sure there weren't any changes in Sphinx that would cause us to do something else. Thank you for the work sleuthing it out!