The link to package.json in the v4 docs was linking to package.json in the v3 source. Fixed to point to the correct v4 location. A change like this will need to be made for all branches on version 4 if you want the docs to be linked correctly (github may be smart enough to follow the link to the current branch if you are on github but it was wrong from the main site).
* Fix incorrect code indentation
* Remove unnecessary vendor prefix for `box-sizing` - all modern browsers now support this unprefixed
* Remove incorrect `<label>` and change static controls to readonly inputs
* Allow `<img>` elements without `src` to allow for `holder.js` images used in the docs, which lack `src` and use `data-src` instead
— Previously we weren't including the border-width on the computed height, leading to alignment issues.
— New system utilizes three variables (not ideal, but straightforward) for computing these heights. One for the vertical border, one for the line-height/font-size/padding dance, and one to add those together.
— Updates CSS across forms and custom forms to use new sizing. Special note here: form validation icon sizing uses the inner variables because background-image doesn't bleed into borders unless explicit background-clip.
Same hack as in https://github.com/twbs/bootstrap/pull/22426 (modulo the selector, which is wrong in that PR and will be updated in a separate PR) to get tooltips to work correctly on iOS. Dynamically adds/removes empty (`noop`) `touchstart` event handlers to all children of `<body>` in order to coax iOS into proper event delegation/bubbling
As the question often comes up about why Bootstrap does not do "true"
ARIA menus (with their `role="menu"` etc), add an admittedly lengthy
note (tl;dr because BS is generic, and ARIA menus are specific and quite
limiting).
Additionally, fixes up the `<a>` example for dropdown trigger, with the
missing `role="button"` and neutering the `href` (which would be useless
anyway since BS overrides the link-like nature of the `<a>` so it could
never be triggered/followed anyway)
