Small doc fixes [skip CI]
Small doc fixes [skip CI]


Former-commit-id: 4fe31873daa46c545274cf33ca83595c3c37e13f [formerly 4fe31873daa46c545274cf33ca83595c3c37e13f [formerly 6b7df72ea16e99ef95d18391c3f8a986c7afb987]]
Former-commit-id: 5ba0712003d83dd52df1f42ff8c536270d059cc0
Former-commit-id: 8eda549e5a48fd2e811502e798123cf7f59ae03a
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine