docs: fix links

docs/design.mld

@@ -17,7 +17,7 @@ We realized there are two distinct use modes when coming to message reporting:
 + One is focusing on {b free-form texts,} which means one directly specifies the long explanation every time a diagnostic is sent; the messages are only a loose categorization of the long explanations.
 + The other is focusing on {b fully structured messages,} which means one directly specifies a structured message (e.g., an element of a variant type) and the long explanation is {i determined} by the message. The message captures all information in the long explanation.
 
-We should support at least the free-form use mode, and ideally support both. The free-form reporting is implemented as {{!module:Asai.Reporter}Reporter} and the structured one is implemented as {{!module:Asai.StructuredReporter}StructuredReporter}.
+We should support at least the free-form use mode, and ideally support both. The free-form reporting is implemented as {{!module:Asai.Reporter}Reporter} and the structured one is implemented as {{!module:Asai.Structured_reporter}Structured_reporter}.
 
 {1 Compositionality: Using Libraries that Use [asai]}