Allow semicolons as only content of blocks

Fixes #300

corpus/definitions.txt

@@ -418,6 +418,12 @@ object O4 extends {
   val a: A = b
 }
 
+object O5 {
+  ;;
+  ;
+  ;
+}
+
 --------------------------------------------------------------------------------
 
 (compilation_unit
@@ -440,7 +446,10 @@ object O4 extends {
         (val_definition
           (identifier)
           (type_identifier)
-          (identifier))))))
+          (identifier)))))
+  (object_definition
+    (identifier)
+    (template_body)))
 
 ================================================================================
 Object definitions

corpus/expressions.txt

@@ -669,6 +669,8 @@ def matchTest(x: Int): String = x match {
   case 3 => {
     "3"
   }
+  case 4 => 
+    ;
   case A if a == 1 =>
   case A if a == 2 => 2
   case ((i, _)) => i
@@ -706,6 +708,8 @@ def matchTest(x: Int): String = x match {
           (integer_literal)
           (block
             (string)))
+        (case_clause
+          (integer_literal))
         (case_clause
           (identifier)
           (guard

grammar.js

@@ -780,7 +780,7 @@ module.exports = grammar({
         seq(
           sep1(
             $._semicolon,
-            choice($.expression, $._definition, $._end_marker),
+            choice($.expression, $._definition, $._end_marker, ";"),
           ),
           optional($._semicolon),
         ),