[cleanup] Show a FutureWarning with deprecated api.ParamInfo.modules

Change-Id: I7d230cd3cd3346ebfc91eea7101665527cbab867
---
M pywikibot/data/api.py
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pywikibot/data/api.py b/pywikibot/data/api.py
index c9f69a7..37e5339 100644
--- a/pywikibot/data/api.py
+++ b/pywikibot/data/api.py
@@ -657,7 +657,8 @@
         return param_data[0]
 
     @property
-    @deprecated('submodules() or module_paths', since='20150715')
+    @deprecated('submodules() or module_paths', since='20150715',
+                future_warning=True)
     def modules(self) -> Union[Set[str], FrozenSet[str]]:
         """
         Set of all main and query modules without path prefixes.

