searchform.php override not working

I'm taking a Udemy class to learn how to make Wordpress plugins and themes. The video I'm on is having me override the default search widget with a custom one via searchform.php. From what I've gathered, this file should automatically be loaded with the rest of the theme as long as I have followed these steps:

/theme_dir/functions.php

/* Some other code */
include ( get_theme_file_path('/includes/widgets.php') );
add_action(widgets_init, 'ju_widgets');

/theme_dir/includes/widgets.php

function ju_widgets() {
    register_sidebar([
        'name'          = __('My First Theme Sidebar', 'udemy'),
        'id'            = 'ju_sidebar',
        'description'   = __('Sidebar for the theme Udemy', 'udemy'),
        'before_widget' = 'div id=%1$s class=widget clearfix %2$s',
        'after_widget'  = '/div',
        'before_title'  = 'h4',
        'after_title'   = '/h4',
    ]);
}

/theme_dir/sidebar.php

div class=sidebar nobottommargin col_last
    div class=sidebar-widgets-wrap
        ?php
            if (is_active_sidebar('ju_sidebar')) {
                dynamic_sidebar('ju_sidebar');
            }
        ?
    /div
/div

/theme_dir/searchform.php

?php $unique_id = esc_attr( uniqid( 'search-form-' ) ); ?

form role=search method=get class=search-form
      action=?php echo esc_url( home_url( '/' ) ); ?
    div class=input-group
        input type=search id=?php echo $unique_id; ?
               class=form-control name=s
               value=?php the_search_query(); ?
               placeholder=?php _e( 'Search', 'udemy' ); ?/
        span class=input-group-btn
            button type=submit class=btn btn-dangeri class=icon-search/i/button
        /span
    /div
/form

/theme_dir/index.php

!-- some theme html --

?php get_sidebar(); ?

!-- other theme html --

No matter what I change in the searchform.php file, it doesn't replace the default search widget.