Update bitbucket.md to fix typo and small grammar touchups.
Update bitbucket.md to fix typo and small grammar touchups.

mmkassem/gitlabhq,stoplightio/gitlabhq,dreampet/gitlab,iiet/iiet-git,iiet/iiet-git,dreampet/gitlab,stoplightio/gitlabhq,jirutka/gitlabhq,stoplightio/gitlabhq,dreampet/gitlab,axilleas/gitlabhq,iiet/iiet-git,mmkassem/gitlabhq,axilleas/gitlabhq,mmkassem/gitlabhq,iiet/iiet-git,axilleas/gitlabhq,jirutka/gitlabhq,jirutka/gitlabhq,mmkassem/gitlabhq,jirutka/gitlabhq,dreampet/gitlab,stoplightio/gitlabhq,axilleas/gitlabhq