Allow creating Autocompletes with 'show_view_link' => true

[dlh01]

This field currently generates a FM_Developer_Exception:

add_action( 'fm_post', function ( $type ) {
	$fm = new \Fieldmanager_Autocomplete( 'Foo', [
		'name' => 'foo',
		'show_view_link' => true,
		'datasource' => new \Fieldmanager_Datasource_Post(),
	] );
	$fm->add_meta_box( 'Bar', $type );
} );

because show_view_link is not a property on \Fieldmanager_Autocomplete. But everything else seems to be set up for it to work (with posts and terms, anyway).

A workaround is to just set $fm->show_view_link = true after instantiating the class.