Fix double-semicolon grammar on resource methods (#268)

Closes #267

Author: alexcrichton

design/mvp/WIT.md

@@ -1194,7 +1194,7 @@ Specifically, the syntax for a `resource` definition is:
 ```ebnf
 resource-item ::= 'resource' id ';'
                 | 'resource' id '{' resource-method* '}'
-resource-method ::= func-item ';'
+resource-method ::= func-item
                   | id ':' 'static' func-type ';'
                   | 'constructor' param-list ';'
 ```