fix spelling

BS3 commit e245bffe8c951a0bba2bb045fb6bbe674d471693
_includes/social-buttons.html: escape ampersands in URLs to fix HTML validation error

BS3 commit 7f8f1ca65e6d908da5dce4536c3d4d5f055dc6a7
social-buttons.html: drop 'px' from height+width attrs per HTML5

BS3 commit e6e60d325ca69010f1334283140dfd2a2ee3cc74
mention 9282 in docs browser section

BS3 commit 3f2408f9e8cbdf359fdc587a8b463c06860162f4
fix ID of <select> in fieldset[disabled] example

BS3 commit 1c64c8f43bece9a2e97be510266c48969dca0963
Validation states docs: fix closing tag

BS3 commit 4876a3a7162ea2be8b1c316fde1039d22a6b64d3
add alt text to carousel <img>s

BS3 commit df59ecc9c40534e34a140cb5a00607c50b2b500c
add alt text to thumbnail <img>s

BS3 commit 5b9717ef67e679d3ae2a70023d042136db00ce71