Help: Revise ctest_* command documentation (#15559)

Revise documentation for the major dashboard client step ``ctest_*``
commands.  Modernize the documentation formatting.  Add some missing
options.

1 files changed, 19 insertions, 10 deletions

diff --git a/Help/command/ctest_update.rst b/Help/command/ctest_update.rst
index 01e357b..74af1f7 100644
--- a/Help/command/ctest_update.rst
+++ b/Help/command/ctest_update.rst
@@ -1,18 +1,27 @@
 ctest_update
 ------------
 
-Update the work tree from version control.
+Perform the :ref:`CTest Update Step` as a :ref:`Dashboard Client`.
 
 ::
 
-  ctest_update([SOURCE source] [RETURN_VALUE res] [QUIET])
+  ctest_update([SOURCE <source-dir>] [RETURN_VALUE <result-var>] [QUIET])
 
-Updates the given source directory and stores results in Update.xml.
-If no SOURCE is given, the CTEST_SOURCE_DIRECTORY variable is used.
-The RETURN_VALUE option specifies a variable in which to store the
-result, which is the number of files updated or -1 on error.
+Update the source tree from version control and record results in
+``Update.xml`` for submission with the :command:`ctest_submit` command.
 
-If QUIET is specified then CTest will suppress most non-error
-messages that it would have otherwise printed to the console.
-CTest will still report the new revision of the repository
-and any conflicting files that were found.
+The options are:
+
+``SOURCE <source-dir>``
+  Specify the source directory.  If not given, the
+  :variable:`CTEST_SOURCE_DIRECTORY` variable is used.
+
+``RETURN_VALUE <result-var>``
+  Store in the ``<result-var>`` variable the number of files
+  updated or ``-1`` on error.
+
+``QUIET``
+  Tell CTest to suppress most non-error messages that it would
+  have otherwise printed to the console.  CTest will still report
+  the new revision of the repository and any conflicting files
+  that were found.