doc en: add 'W' pragma as supported list
doc en: add 'W' pragma as supported list

naoa/mroonga,yoku0825/mroonga,mroonga/mroonga,yoku0825/mroonga,mroonga/mroonga,yoku0825/mroonga,naoa/mroonga,naoa/mroonga,mroonga/mroonga,naoa/mroonga,mroonga/mroonga,naoa/mroonga,yoku0825/mroonga,yoku0825/mroonga,naoa/mroonga,yoku0825/mroonga