docs: make the first letter capital

kenjis · kenjis · commit 4a4e8d6048ef · 2023-02-20T09:10:43.000+09:00
diff --git a/user_guide_src/source/incoming/filters.rst b/user_guide_src/source/incoming/filters.rst
@@ -152,8 +152,8 @@ a list of URI patterns that filter should apply to:
 
 .. literalinclude:: filters/009.php
 
-Filter arguments
-=================
+Filter Arguments
+================
 
 When configuring filters, additional arguments may be passed to a filter when setting up the route:
 
