Change grammar so that an annotation is always followed by semicolon

This matches how annotations are placed in other parts of the grammar.

RationaleMCP/0031/grammar.md

@@ -177,12 +177,14 @@ end _F;
 ## Clock partitions
 
 > _base-partition_ →\
->   **partition** _comment_\
+>   **partition** _string-comment_\
+>   ( _annotation-comment_ **;** )?
 >   _clock-clause_ **;**\
 >   _sub-partition_*
 
 > _sub-partition_ →\
->   **subpartition** _comment_\
+>   **subpartition** _string-comment_\
+>   ( _annotation-comment_ **;** )?
 >   ( **discretization** _STRING_ **;** )?\
 >   _clock-clause_ **;**\
 >   ( **equation** ( _equation_ **;** )* \