Update parallel launcher docs

Author: vkarak

docs/config_reference.rst

@@ -518,8 +518,10 @@ System Partition Configuration
      The program will be launched locally.
    - ``lrun``: Parallel programs will be launched using `LC Launcher  <https://hpc.llnl.gov/training/tutorials/using-lcs-sierra-system#lrun>`__'s ``lrun`` command.
    - ``lrun-gpu``: Parallel programs will be launched using `LC Launcher <https://hpc.llnl.gov/training/tutorials/using-lcs-sierra-system#lrun>`__'s ``lrun -M "-gpu"`` command that enables the CUDA-aware Spectrum MPI.
-   - ``mpirun``: Parallel programs will be launched using the ``mpirun`` command.
    - ``mpiexec``: Parallel programs will be launched using the ``mpiexec`` command.
+   - ``mpirun``: Parallel programs will be launched using the (generic) ``mpirun`` command.
+   - ``mpirun-intelmpi``: Parallel programs will be launched using the Intel MPI's ``mpirun`` command.
+   - ``mpirun-openmpi``: Parallel programs will be launched using the OpenMPI's ``mpirun`` command.
    - ``pdsh``: Parallel programs will be launched using the ``pdsh`` command. This launcher uses the partition's :attr:`~config.systems.partitions.access` property in order to determine the options to be passed to ``pdsh``.
    - ``srun``: Parallel programs will be launched using `Slurm <https://slurm.schedmd.com/srun.html>`__'s ``srun`` command.
    - ``srunalloc``: Parallel programs will be launched using `Slurm <https://slurm.schedmd.com/srun.html>`__'s ``srun`` command, but job allocation options will also be emitted.
@@ -542,6 +544,10 @@ System Partition Configuration
    - ``upcrun``: Parallel programs will be launched using the `UPC <https://upc.lbl.gov/>`__ ``upcrun`` command.
    - ``upcxx-run``: Parallel programs will be launched using the `UPC++ <https://bitbucket.org/berkeleylab/upcxx/wiki/Home>`__ ``upcxx-run`` command.
 
+   .. versionadded:: 4.9
+
+      The ``mpirun-intelmpi`` and ``mpirun-openmpi`` parallel launchers were added.
+
    .. tip::
 
       .. versionadded:: 4.0.0

reframe/core/launchers/__init__.py

@@ -40,14 +40,16 @@ class JobLauncher(metaclass=_JobLauncherMeta):
     #: invocation. The keys are the variable names and the values are their
     #: corresponding values.
     #:
-    #: This is supported by the following launchers:
+    #: This is supported by the following launchers only:
     #:
     #: - ``srun``
     #: - ``mpirun-openmpi``
     #: - ``mpirun-intelmpi``
     #:
     #: :type: :class:`Dict[str, str]`
     #: :default: ``{}``
+    #:
+    #: .. versionadded:: 4.9
     env_vars = variable(typ.Dict[str, str], value={})
 
     #: Optional modifier of the launcher command.

reframe/core/launchers/mpi.py

@@ -54,6 +54,7 @@ def command(self, job):
 
         return ret
 
+
 @register_launcher('ibrun')
 class IbrunLauncher(JobLauncher):
     '''TACC's custom parallel job launcher.'''