https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=879986...
To fix this, add a comma at the end of line 32, after 'squeeze'.
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Update:
Fixed in vim (2:8.0.1257-1)
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* syntax/debsources.vim:
+ Fix syntax error in definition of unsupported releases. Thanks to Josh
Triplett. (Closes: #879986)
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