Fixed a typo in docs/assets/css/docs.css

only stop prop on form – as people seem to be relying on dropdown hiding when clicking internal elements

i18n tags missing in some strings at getting started download page

fixes #4718: add vertical-align: middle; to .btn-group to ensure proper alignment next to standard .btn

fixes #4640: pagination span issues resolved by scoping selectors to appropriate children, not all children; clarify docs on use of spans for disabled and active links