autotest: param_parse.py: whitespace-only line is param block delimiter

Several parameters were missing from the documentation because there was
a line with just trailing whitespace immediately after a parameter
metadata block.

Be more lenient.

Tools/autotest/param_metadata/param_parse.py

@@ -34,7 +34,7 @@ args = parser.parse_args()
 
 # Regular expressions for parsing the parameter metadata
 
-prog_param = re.compile(r"@Param: (\w+).*((?:\n[ \t]*// @(\w+)(?:{([^}]+)})?: (.*))+)(?:\n\n|\n[ \t]+[A-Z])", re.MULTILINE)
+prog_param = re.compile(r"@Param: (\w+).*((?:\n[ \t]*// @(\w+)(?:{([^}]+)})?: (.*))+)(?:\n[ \t]*\n|\n[ \t]+[A-Z])", re.MULTILINE)
 
 # match e.g @Value: 0=Unity, 1=Koala, 17=Liability
 prog_param_fields = re.compile(r"[ \t]*// @(\w+): (.*)")