std.zig.parser: Refactored `commaOrEnd` to `expectCommaOrEnd`

* Now it returns end when found, or null if comma was found.
* State should now be appended outside the function
d35a6655e0Jimmi Holst Christensen committed on 4/12/2018, 4:13:09 PMparent206c0b8
1 file changedLine totals unavailable