ValueError: Missing delimiter in dictionary before content

Hello,

With version 5.2.0
```
€ wget https://github.com/antijingoist/opendyslexic/archive/v0.91.12.tar.gz
€ tar xf v0.91.12.tar.gz
€ cd opendyslexic-0.91.12/sources/opendyslexic
€ glyphs2ufo opendyslexic.glyphs
Traceback (most recent call last):
File "/usr/bin/glyphs2ufo", line 33, in
sys.exit(load_entry_point('glyphsLib==5.2.0', 'console_scripts', 'glyphs2ufo')())
File "/usr/lib/python3/dist-packages/glyphsLib/cli.py", line 228, in _glyphs2ufo_entry_point
return main(args)
File "/usr/lib/python3/dist-packages/glyphsLib/cli.py", line 189, in main
return options.func(options)
File "/usr/lib/python3/dist-packages/glyphsLib/cli.py", line 208, in glyphs2ufo
glyphsLib.build_masters(
File "/usr/lib/python3/dist-packages/glyphsLib/__init__.py", line 104, in build_masters
font = GSFont(filename)
File "/usr/lib/python3/dist-packages/glyphsLib/classes.py", line 3653, in __init__
p.parse_into_object(self, fp.read())
File "/usr/lib/python3/dist-packages/glyphsLib/parser.py", line 63, in parse_into_object
i = self._parse_dict_into_object(res, text, 1)
File "/usr/lib/python3/dist-packages/glyphsLib/parser.py", line 166, in _parse_dict_into_object
result = self._parse(text, i)
File "/usr/lib/python3/dist-packages/glyphsLib/parser.py", line 103, in _parse
return self._parse_list(text, i)
File "/usr/lib/python3/dist-packages/glyphsLib/parser.py", line 193, in _parse_list
list_item, i = self._parse(text, i)
File "/usr/lib/python3/dist-packages/glyphsLib/parser.py", line 97, in _parse
return self._parse_dict(text, i)
File "/usr/lib/python3/dist-packages/glyphsLib/parser.py", line 150, in _parse_dict
i = self._parse_dict_into_object(res, text, i)
File "/usr/lib/python3/dist-packages/glyphsLib/parser.py", line 166, in _parse_dict_into_object
result = self._parse(text, i)
File "/usr/lib/python3/dist-packages/glyphsLib/parser.py", line 103, in _parse
return self._parse_list(text, i)
File "/usr/lib/python3/dist-packages/glyphsLib/parser.py", line 193, in _parse_list
list_item, i = self._parse(text, i)
File "/usr/lib/python3/dist-packages/glyphsLib/parser.py", line 97, in _parse
return self._parse_dict(text, i)
File "/usr/lib/python3/dist-packages/glyphsLib/parser.py", line 150, in _parse_dict
i = self._parse_dict_into_object(res, text, i)
File "/usr/lib/python3/dist-packages/glyphsLib/parser.py", line 176, in _parse_dict_into_object
self._fail("Missing delimiter in dictionary before content", text, i)
File "/usr/lib/python3/dist-packages/glyphsLib/parser.py", line 235, in _fail
raise ValueError("{}:\n{}".format(message, text[i : i + 79]))
ValueError: Missing delimiter in dictionary before content:
Value;
}
);
descender = -520;
guideLines = (
{
angle = 90;
position = "{259, 1
```

Samuel

Reproduce the failure with the reported opendyslexic.glyphs download and glyphs2ufo command, then start in glyphsLib/parser.py at _parse_dict_into_object and the _fail call. Inspect the text around the reported “Value;” location and determine the expected handling for this input; done requires an agreed behavior and a regression test or confirmed diagnostic.

Written by the indexing model from the issue text.