Update doc to reflect change of: from-pr -> from-commit

Author: Neves-P

docs/adding_software/contribution_policy.md

@@ -58,8 +58,8 @@ We currently require that all software installations in EESSI are
 We strongly prefer that the [*latest release of EasyBuild*](https://pypi.org/project/easybuild/)
 that is available at the time is used to add software to EESSI.
 
-The use of [`--from-pr`](https://docs.easybuild.io/integration-with-github/#github_from_pr) and
-[`--include-easyblocks-from-pr`](https://docs.easybuild.io/integration-with-github/#github_include_easyblocks_from_pr)
+The use of [`--from-commit`](https://docs.easybuild.io/integration-with-github/#github_from_commit) and
+[`--include-easyblocks-from-commit`](https://docs.easybuild.io/integration-with-github/#github_include_easyblocks_from_commit)
 to pull in changes to EasyBuild that are required to make the installation work correctly
 in EESSI is allowed, but only if that is strictly required
 (that is, if those changes are not included yet in the latest EasyBuild release).