Relax font validation in the config

Fixes #2256

CHANGELOG.asciidoc

@@ -44,6 +44,8 @@ Fixed
 - `:download --mhtml` now uses the new file dialog
 - Insert mode now gets entered correctly with a non-100% zoom
 - Word hints are now upper-cased correctly when hints -> uppercase is true
+- Font validation is now more permissive in the config, allowing e.g. "Terminus
+  (TTF)" as font name.
 
 v0.9.1
 ------

qutebrowser/config/configtypes.py

@@ -741,9 +741,9 @@ class Font(BaseType):
                 ) |
                 # size (<float>pt | <int>px)
                 (?P<size>[0-9]+((\.[0-9]+)?[pP][tT]|[pP][xX]))
-            )\                         # size/weight/style are space-separated
-        )*                             # 0-inf size/weight/style tags
-        (?P<family>[A-Za-z0-9, "-]*)$  # mandatory font family""", re.VERBOSE)
+            )\           # size/weight/style are space-separated
+        )*               # 0-inf size/weight/style tags
+        (?P<family>.+)$  # mandatory font family""", re.VERBOSE)
 
     def validate(self, value):
         self._basic_validation(value)

tests/unit/config/test_configtypes.py

@@ -978,6 +978,8 @@ class TestFont:
         'inconsolatazi4':
             FontDesc(QFont.StyleNormal, QFont.Normal, -1, -1,
                      'inconsolatazi4'),
+        'Terminus (TTF)':
+            FontDesc(QFont.StyleNormal, QFont.Normal, -1, -1, 'Terminus (TTF)'),
         '10pt "Foobar Neue"':
             FontDesc(QFont.StyleNormal, QFont.Normal, 10, None, 'Foobar Neue'),
         '10PT "Foobar Neue"':
@@ -1042,7 +1044,7 @@ class TestFont:
         font_xfail('green'),
         font_xfail('10pt'),
         font_xfail('10pt ""'),
-        '%',
+        '',
     ])
     def test_validate_invalid(self, klass, val):
         with pytest.raises(configexc.ValidationError):
@@ -1102,7 +1104,6 @@ class TestFontFamily:
         'normal bold 10pt "Foobar Neue"',
         'bold italic 10pt "Foobar Neue"',
         '',  # with none_ok=False
-        '%',
     ]
 
     @pytest.fixture