minor typo documentation
Merge branch 'master' of github.com:ixa-ehu/ixa-pipe-nerc
Merge branch 'master' of github.com:ixa-ehu/ixa-pipe-nerc
Merge branch 'master' of github.com:ixa-ehu/ixa-pipe-nerc
Merge branch 'master' of github.com:ixa-ehu/ixa-pipe-nerc
doc update