Fixed small typos in GW tutorial
Fixed small typos in GW tutorial

alexandremorlet/yambopy,palful/yambopy,alexmoratalla/yambopy,henriquemiranda/yambo-py,alexmoratalla/yambo-py,palful/yambopy,alexandremorlet/yambopy,henriquemiranda/yambopy,henriquemiranda/yambopy,alexmoratalla/yambo-py,alexmoratalla/yambopy,henriquemiranda/yambo-py