Parser: fixed wrong parsing of tuple with one element followed by new…

…line and brace. Fixes #3779

spec/compiler/parser/parser_spec.cr

@@ -1022,6 +1022,8 @@ describe "Parser" do
   it_parses "{1, 2, 3}", TupleLiteral.new([1.int32, 2.int32, 3.int32] of ASTNode)
   it_parses "{A::B}", TupleLiteral.new([Path.new(["A", "B"])] of ASTNode)
   it_parses "{\n1,\n2\n}", TupleLiteral.new([1.int32, 2.int32] of ASTNode)
+  it_parses "{\n1\n}", TupleLiteral.new([1.int32] of ASTNode)
+  it_parses "{\n{1}\n}", TupleLiteral.new([TupleLiteral.new([1.int32] of ASTNode)] of ASTNode)
 
   it_parses "foo { a = 1 }; a", [Call.new(nil, "foo", block: Block.new(body: Assign.new("a".var, 1.int32))), "a".call] of ASTNode
 

src/compiler/crystal/syntax/parser.cr

@@ -2102,6 +2102,10 @@ module Crystal
             return parse_tuple first_key, location
           when :"}"
             return parse_tuple first_key, location
+          when :NEWLINE
+            next_token_skip_space
+            check :"}"
+            return parse_tuple first_key, location
           else
             check :"=>"
           end