Replace fairshare with fair-share

.spelling

docs.it4i/anselm-cluster-documentation/job-priority.md

...er-documentation/resource-allocation-and-job-execution.md

...selm-cluster-documentation/resources-allocation-policy.md

docs.it4i/salomon/job-priority.md

docs.it4i/salomon/resource-allocation-and-job-execution.md

docs.it4i/salomon/resources-allocation-policy.md