Remove the RedirectResponse code and correct the form edit button text

Hi B N Pandey,

There are some issues at some places like.

1. In EditLocation.php file you have used

$redirect = new RedirectResponse($base_url . '/admin/structure/gmap-location');
$redirect->send();

Correct way to redirect form is
$form_state->setRedirectUrl($url);

2. Same issue in file "MapLocationDelete.php"

$redirect = new RedirectResponse($base_url . '/admin/structure/gmap-location');
$redirect->send();

Correct way to redirect form is
$form_state->setRedirectUrl($url);

3. Wrong button name on edit location page.
Current button say "Add location"
Correct text is Update Location