Update docs

docs/misc_api.md

@@ -90,9 +90,9 @@ __Arguments__
 
 
 - __distro (string)__: Valid values are `centos7`, `centos8`, `rhel7`,
-`rhel8`, `rockylinux8`, `ubuntu16`, `ubuntu18`, `ubuntu20`, and
-`ubuntu22`.  `ubuntu` is an alias for `ubuntu16`, `centos` is an
-alias for `centos7`, and `rhel` is an alias for `rhel7`.
+`rhel8`, `rockylinux8`, `rockylinux9`, `ubuntu16`, `ubuntu18`, `ubuntu20`,
+`ubuntu22`, and `ubuntu24`.  `ubuntu` is an alias for `ubuntu16`, `centos`
+is an alias for `centos7`, and `rhel` is an alias for `rhel7`.
 
 
 ## set_singularity_version

docs/primitives.md

@@ -22,11 +22,11 @@ is `docker` (Singularity specific).
 
 - ___distro__: The underlying Linux distribution of the base image.
 Valid values are `centos`, `centos7`, `centos8`, `redhat`, `rhel`,
-`rhel7`, `rhel8`, `rockylinux8`, `ubuntu`, `ubuntu16`, `ubuntu18`,
-`ubuntu20`, and `ubuntu22`.  By default, the primitive attempts to
-figure out the Linux distribution by inspecting the image
-identifier, and falls back to `ubuntu` if unable to determine the
-Linux distribution automatically.
+`rhel7`, `rhel8`, `rockylinux8`, `rockylinux9`, `ubuntu`, `ubuntu16`,
+`ubuntu18`, `ubuntu20`, `ubuntu22`, and `ubuntu24`.  By default, the
+primitive attempts to figure out the Linux distribution by inspecting
+the image identifier, and falls back to `ubuntu` if unable to determine
+the Linux distribution automatically.
 
 - ___docker_env__: Boolean specifying whether to load the Docker base
  image environment, i.e., source