Menu Machine Name as Class attribute in the wrapper element

#2 patch is apply successfully. I have attached the after and before attachment.

+++ b/templates/menu/menu.html.twig
@@ -21,15 +21,15 @@
+      <ul{{ attributes.addClass('menu', 'nav', menu_name) }}>
...
+      <ul{{ attributes.addClass('dropdown-menu', menu_name) }}>

Since this is a variable (machine name), then it should use the |clean_class filter as well when adding it.

@bandanasharma, taking screenshots of code changes isn't necessary and honestly, a little confusing; that is what the patch is for.

Screenshots are typically only useful for changes that affect the UI/site itself.

The last patch looks good.

I might have missed something but I see that the following code was directly removed? Was that by design?

 <a href="{{ item.url }}" class="dropdown-toggle" data-target="#" data-toggle="dropdown">{{ item.title }} <span class="caret"></span></a>

There was a lot of markup/line changes between #2 and #7. I just asked that the |clean_class filter was applied. I don't think the level of complexity in #7 is needed.

+++ b/templates/menu/menu.html.twig
@@ -21,15 +21,16 @@
+{% set menu_name = menu_name | clean_class  %}

Never override existing variables in templates. This can cause unintended and unforeseen issues when attempting to extend or override in sub-themes.

The filter should be used like the following (without spaces around the pipe):
<ul{{ attributes.addClass('dropdown-menu', menu_name|clean_class) }}>

Just an FYI: #2936370: Consolidate menu macro in main template

This adds a menu-- prefix to the menu name.