docs: a few more miscellaneous RST format updates

Just putting some text in fixed-width font, etc.  No text or content
changes.

Signed-off-by: Jeff Squyres <jeff@squyres.com>

Author: jsquyres

docs/man-openmpi/man3/MPI_Comm_create_keyval.3.rst

@@ -75,13 +75,13 @@ deprecated. The C binding is identical. The Fortran binding differs in
 that ``extra_state`` is an address-sized integer. Also, the copy and
 delete callback functions have Fortran bindings that are consistent with
 address-sized attributes. The argument ``comm_copy_attr_fn`` may be
-specified as MPI_COMM_NULL_COPY_FN or MPI_COMM_DUP_FN from C or
-Fortran. MPI_COMM_NULL_COPY_FN is a function that does nothing more
-than returning ``flag = 0`` and MPI_SUCCESS. MPI_COMM_DUP_FN is
+specified as ``MPI_COMM_NULL_COPY_FN`` or ``MPI_COMM_DUP_FN`` from C or
+Fortran. ``MPI_COMM_NULL_COPY_FN`` is a function that does nothing more
+than returning ``flag = 0`` and ``MPI_SUCCESS``. ``MPI_COMM_DUP_FN`` is
 a simple-minded copy function that sets ``flag = 1``, returns the value
 of ``attribute_val_in`` in ``attribute_val_out``, and returns
-MPI_SUCCESS. These replace the MPI-1 predefined callbacks
-MPI_NULL_COPY_FN and MPI_DUP_FN, the use of which is deprecated.
+``MPI_SUCCESS``. These replace the MPI-1 predefined callbacks
+``MPI_NULL_COPY_FN`` and ``MPI_DUP_FN``, the use of which is deprecated.
 The two C callback functions are:
 
 .. code-block:: c

docs/man-openmpi/man3/MPI_Errhandler_create.3.rst

@@ -82,7 +82,7 @@ The `MPI Standard <https://www.mpi-forum.org/docs/>`_ states that an
 implementation may make the output
 value (errhandler) simply the address of the function. However, the
 action of :ref:`MPI_Errhandler_free` makes this impossible, since it is
-required to set the value of the argument to MPI_ERRHANDLER_NULL. In
+required to set the value of the argument to ``MPI_ERRHANDLER_NULL``. In
 addition, the actual error handler must remain until all communicators
 that use it are freed.
 

docs/man-openmpi/man3/MPI_Get_count.3.rst

@@ -65,7 +65,7 @@ provided by the receive call that set the status variable. As explained
 in the "Use of General Datatypes in Communication" section of the `MPI
 Standard <https://www.mpi-forum.org/docs/>`_.
 :ref:`MPI_Get_count` may, in certain situations, return the value
-MPI_UNDEFINED.
+``MPI_UNDEFINED``.
 
 The datatype argument is passed to :ref:`MPI_Get_count` to improve performance.
 A message might be received without counting the number of elements it
@@ -78,14 +78,14 @@ NOTES
 If the size of the datatype is zero, this routine will return a count of
 zero. If the amount of data in status is not an exact multiple of the
 size of datatype (so that count would not be integral), a count of
-MPI_UNDEFINED is returned instead.
+``MPI_UNDEFINED`` is returned instead.
 
 ERRORS
 ------
 
 .. include:: ./ERRORS.rst
 
 If the value to be returned is larger than can fit into the count
-parameter, an MPI_ERR_TRUNCATE error is raised.
+parameter, an ``MPI_ERR_TRUNCATE`` error is raised.
 
 .. seealso:: :ref:`MPI_Get_elements`

docs/man-openmpi/man3/MPI_Type_get_contents.3.rst

@@ -107,15 +107,15 @@ of attributes of returned data types is undefined.
 Note that :ref:`MPI_Type_get_contents` can be invoked with a data-type argument
 that was constructed using :ref:`MPI_Type_create_f90_real`,
 :ref:`MPI_Type_create_f90_integer`, or :ref:`MPI_Type_create_f90_complex` (an unnamed
-predefined data type). In such a case, an empty *array_of_datatypes is
-returned.*
+predefined data type). In such a case, an empty *array_of_datatypes* is
+returned.
 
 In the legacy MPI-1 datatype constructor calls, the address arguments in
 Fortran are of type ``INTEGER``. In subsequent versions of the `MPI
 Standard <https://www.mpi-forum.org/docs/>`_, the address
 arguments are of type ``INTEGER(KIND=MPI_ADDRESS_KIND)``. The call
 :ref:`MPI_Type_get_contents` returns all addresses in an argument of type
-INTEGER(KIND=MPI_ADDRESS_KIND). This is true even if the old MPI-1 calls
+``INTEGER(KIND=MPI_ADDRESS_KIND)``. This is true even if the old MPI-1 calls
 were used. Thus, the location of values returned can be thought of as
 being returned by the C bindings. It can also be determined by examining
 the new MPI-2 calls for data-type constructors for the deprecated MPI-1