Help: Improve 'cmake -E md5sum' documentation

Help/manual/cmake.1.rst

@@ -204,7 +204,10 @@ Available commands are:
   silently ignored.
 
 ``md5sum <file>...``
-  Compute md5sum of files.
+  Create MD5 checksum of files in ``md5sum`` compatible format::
+
+     351abe79cd3800b38cdfb25d45015a15  file1.txt
+     052f86c15bbde68af55c7f7b340ab639  file2.txt
 
 ``remove [-f] <file>...``
   Remove the file(s), use ``-f`` to force it.  If a file does

Source/cmcmd.cxx

@@ -70,7 +70,7 @@ void CMakeCommandUsage(const char* program)
     << "                            - run command in a modified environment\n"
     << "  environment               - display the current environment\n"
     << "  make_directory <dir>...   - create parent and <dir> directories\n"
-    << "  md5sum <file>...          - compute md5sum of files\n"
+    << "  md5sum <file>...          - create MD5 checksum of files\n"
     << "  remove [-f] <file>...     - remove the file(s), use -f to force "
        "it\n"
     << "  remove_directory dir      - remove a directory and its contents\n"