multiple with_prototypes at the same stack level are currently unsupported

[keith-hall]

For example, this test, if put in parser.rs, would fail:

#[test]
    fn can_parse_two_with_prototypes_at_same_stack_level() {
        let syntax = r#"
%YAML 1.2
---
# See http://www.sublimetext.com/docs/3/syntax.html
scope: source.example-wp
contexts:
  main:
    - match: a
      scope: a
      push:
        - match: b
          scope: b
          set:
            - match: c
              scope: c
          with_prototype:
            - match: '2'
              scope: '2'
      with_prototype:
        - match: '1'
          scope: '1'
"#;

        let syntax = SyntaxDefinition::load_from_str(&syntax, true, None).unwrap();
        expect_scope_stacks_with_syntax("abc12", &["<1>", "<2>"], syntax);
    }

failures:

---- parsing::parser::tests::can_parse_two_with_prototypes_at_same_stack_level stdout ----
	abc12
^ +source.example-wp
abc12
^ +a
abc12
 ^ pop 1
abc12
 ^ +b
abc12
  ^ pop 1
abc12
  ^ +c
abc12
   ^ pop 1
abc12
    ^ +2
abc12
     ^ pop 1
ScopeStack { clear_stack: [], scopes: [<source.example-wp>] }
ScopeStack { clear_stack: [], scopes: [<source.example-wp>, <a>] }
ScopeStack { clear_stack: [], scopes: [<source.example-wp>] }
ScopeStack { clear_stack: [], scopes: [<source.example-wp>, <b>] }
ScopeStack { clear_stack: [], scopes: [<source.example-wp>] }
ScopeStack { clear_stack: [], scopes: [<source.example-wp>, <c>] }
ScopeStack { clear_stack: [], scopes: [<source.example-wp>] }
ScopeStack { clear_stack: [], scopes: [<source.example-wp>, <2>] }
ScopeStack { clear_stack: [], scopes: [<source.example-wp>] }
thread 'parsing::parser::tests::can_parse_two_with_prototypes_at_same_stack_level' panicked at 'expected scope stack '<1>' missing', src/parsing/parser.rs:1324:13

but using this syntax definition in Sublime Text, the 1 and the 2 both receive scopes.