qapi: Improve error position for bogus argument descriptions

When documented arguments don't exist, the error message points to the
beginning of the definition comment.  Point to the first bogus
argument description instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240216145841.2099240-6-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

scripts/qapi/parser.py

@@ -472,6 +472,8 @@ class QAPIDoc:
         # pylint: disable=too-few-public-methods
         def __init__(self, parser: QAPISchemaParser,
                      name: Optional[str] = None):
+            # section source info, i.e. where it begins
+            self.info = parser.info
             # parser, for error messages about indentation
             self._parser = parser
             # optional section name (argument/member or section name)
@@ -770,7 +772,7 @@ class QAPIDoc:
                      if not section.member]
             if bogus:
                 raise QAPISemError(
-                    self.info,
+                    args[bogus[0]].info,
                     "documented %s%s '%s' %s not exist" % (
                         what,
                         "s" if len(bogus) > 1 else "",