Remove .ruby-version due to https://github.com/twbs/bootstrap/commit/4f20a29c329aa58919919426cbd2190fabfdb723
Merge pull request #10871 from ZDroid/patch-2

Remove .ruby-version from excludes
run grunt
unify button sizing, use mixin ".button-size" also for the base sized button
Correct grammar

Jekyll is the third person singular (it), so it should be 'its documentation', not 'their documentation'.
Merge pull request #10932 from ZDroid/patch-1

Correct grammar