doc: fix gtk+2.0 package name
doc: fix gtk+2.0 package name

grevutiu-gabriel/freshplayerplugin,Papapashu/freshplayerplugin,reuben/freshplayerplugin,Papapashu/freshplayerplugin,reuben/freshplayerplugin,Papapashu/freshplayerplugin,reuben/freshplayerplugin,grevutiu-gabriel/freshplayerplugin