Fixes #4361 wrong error message: unexpected token: end

Replace "expecting when, else or end" with "expecting when or else".

Author: akzhan

spec/compiler/parser/parser_spec.cr

@@ -917,6 +917,7 @@ describe "Parser" do
   it_parses "case a\nwhen b\n1 / 2\nelse\n1 / 2\nend", Case.new("a".call, [When.new(["b".call] of ASTNode, Call.new(1.int32, "/", 2.int32))], Call.new(1.int32, "/", 2.int32))
   it_parses "case a\nwhen b\n/ /\n\nelse\n/ /\nend", Case.new("a".call, [When.new(["b".call] of ASTNode, RegexLiteral.new(StringLiteral.new(" ")))], RegexLiteral.new(StringLiteral.new(" ")))
   assert_syntax_error "case {1, 2}; when {3}; 4; end", "wrong number of tuple elements (given 1, expected 2)", 1, 19
+  assert_syntax_error "case 1; end", "unexpected token: end (expecting when or else)", 1, 9
 
   it_parses "select\nwhen foo\n2\nend", Select.new([Select::When.new("foo".call, 2.int32)])
   it_parses "select\nwhen foo\n2\nwhen bar\n4\nend", Select.new([Select::When.new("foo".call, 2.int32), Select::When.new("bar".call, 4.int32)])

src/compiler/crystal/syntax/parser.cr

@@ -2391,7 +2391,7 @@ module Crystal
             break
           when :end
             if whens.empty?
-              unexpected_token @token.to_s, "expecting when, else or end"
+              unexpected_token @token.to_s, "expecting when or else"
             end
             next_token
             break