Sort command only takes up to two fields as parameter

[51-code]

Describe the bug

Currently the sort command only takes one or two fields as parameters to sort with.

For example the following query will silently result in an error: | sort offset, index, _raw

Expected behavior

Should work with unlimited amount of fields.

How to reproduce

Run a query like this: index=abc | sort offset, index, _raw | eval a=10

it won't execute the eval command at all in since the parse tree is only created as far as the second comma. Furthermore the _raw column isn't taken into account when sorting.

Screenshots

Software version

6.1.0

Desktop (please complete the following information if relevant):

• OS:
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Additional context

sortParseTest in TicketSyntaxTests.java has been disabled because of this issue in PR #52.

[51-code]

index=abc | sort offset index _raw | eval a=10 works. Seems like sort is supported for multiple fields, just not when separating the fields with commas.

[51-code]

Fixed the bug, but implementing #64 to the same PR to make sure nothing else broke when solving this one.