Remove `touch-action:manipulation` click optimization (#25250)

Due to a severe performance bug in Chrome (see https://bugs.chromium.org/p/chromium/issues/detail?id=800522) and due to the fact that (with the exception of IE/Edge on Windows desktop with touchscreen) all modern browsers now optimize the click delay away anyway, this optimization is not needed.

Closes https://github.com/twbs/bootstrap/issues/24670

docs/4.0/content/reboot.md

@@ -363,18 +363,4 @@ HTML5 adds [a new global attribute named `[hidden]`](https://developer.mozilla.o
 `[hidden]` is not compatible with jQuery's `$(...).hide()` and `$(...).show()` methods. Therefore, we don't currently especially endorse `[hidden]` over other techniques for managing the `display` of elements.
 {% endcallout %}
 
-To merely toggle the visibility of an element, meaning its `display` is not modified and the element can still affect the flow of the document, use [the `.invisible` class]({{ site.baseurl }}/docs/{{ site.docs_version }}/utilities/visibility/) instead.
-
+To merely toggle the visibility of an element, meaning its `display` is not modified and the element can still affect the flow of the document, use [the `.invisible` class]({{ site.baseurl }}/docs/{{ site.docs_version }}/utilities/visibility/) instead.
\ No newline at end of file
-## Click delay optimization for touch
-
-Traditionally, browsers on touchscreen devices have a delay of approximately 300ms between the end of a "tap" – the moment when a finger/stylus is lifted from screen – and the [`click` event](https://developer.mozilla.org/en-US/docs/Web/Events/click) being fired. This delay is necessary for these browsers to correctly handle "double-tap to zoom" gestures without prematurely triggering actions or links after the first "tap", but it can make your site feel slightly sluggish and unresponsive.
-
-Most mobile browsers automatically optimize away this 300ms delay for sites that use the `width=device-width` property as part of their [responsive meta tag]({{ site.baseurl }}/docs/{{ site.docs_version }}/getting-started/introduction/#responsive-meta-tag) (as well as for sites that disable zooming, for instance with `user-scalable=no`, though this practice is strongly discouraged for accessibility and usability reasons). The biggest exceptions here are IE11 on Windows Phone 8.1, and iOS Safari (and any other iOS WebView-based browser) [prior to iOS 9.3](https://webkit.org/blog/5610/more-responsive-tapping-on-ios/).
-
-On touch-enabled laptop/desktop devices, IE11 and Microsoft Edge are currently the only browsers with "double-tap to zoom" functionality. As the [responsive meta tag]({{ site.baseurl }}/docs/{{ site.docs_version }}/getting-started/introduction/#responsive-meta-tag) is ignored by all desktop browsers, using `width=device-width` will have no effect on the 300ms delay here.
-
-To address this problem in IE11 and Microsoft Edge on desktop, as well as IE11 on Windows Phone 8.1, Bootstrap explicitly uses the [`touch-action:manipulation` CSS property](https://developer.mozilla.org/en-US/docs/Web/CSS/touch-action) on all interactive elements (such as buttons and links). This property essentially disables double-tap functionality on those elements, eliminating the 300ms delay.
-
-In the case of old iOS versions (prior to 9.3), the suggested approach is to use additional scripts such as [FastClick](https://github.com/ftlabs/fastclick) to explicitly work around the delay.
-
-For further details, see the compatibility table for [suppressing 300ms delay for touchscreen interactions](https://patrickhlauke.github.io/touch/tests/results/#suppressing-300ms-delay).

scss/_reboot.scss

@@ -279,29 +279,6 @@ svg:not(:root) {
 }
 
 
-// Avoid 300ms click delay on touch devices that support the `touch-action` CSS property.
-//
-// In particular, unlike most other browsers, IE11+Edge on Windows 10 on touch devices and IE Mobile 10-11
-// DON'T remove the click delay when `<meta name="viewport" content="width=device-width">` is present.
-// However, they DO support removing the click delay via `touch-action: manipulation`.
-// See:
-// * https://getbootstrap.com/docs/4.0/content/reboot/#click-delay-optimization-for-touch
-// * https://caniuse.com/#feat=css-touch-action
-// * https://patrickhlauke.github.io/touch/tests/results/#suppressing-300ms-delay
-
-a,
-area,
-button,
-[role="button"],
-input:not([type="range"]),
-label,
-select,
-summary,
-textarea {
-  touch-action: manipulation;
-}
-
-
 //
 // Tables
 //