add missing ; in middleware documentation
add missing ; in middleware documentation

kkopachev/guzzle,guzzle/guzzle,michabbb-backup/guzzle,paveljanda/guzzle,Brunty/guzzle,thinsoldier/guzzle,ehough/guzzle,wherefortravel/guzzle,paveljanda/guzzle,kkopachev/guzzle,mortenhauberg/guzzle,thinsoldier/guzzle,michabbb-backup/guzzle,guzzle/guzzle,Tobion/guzzle,Brunty/guzzle,mortenhauberg/guzzle,dshafik/guzzle,Tobion/guzzle,wherefortravel/guzzle,ehough/guzzle,dshafik/guzzle