internal/cuetxtar: use structural_cycle code
Rename the structural cycle error code string from "structural cycle"
(with space) to "structural_cycle" (with underscore) to make it
easier to use in key=value attribute arguments without quoting.
This changes the line comment on StructuralCycleError and regenerates
the stringer output. (The error message text "structural cycle" is
unchanged.)
Update all @test(err, code=structural_cycle) annotations and all
golden-file sections that print "[structural_cycle]" prefixes.
Signed-off-by: Marcel van Lohuizen <mpvl@gmail.com>
Change-Id: Ic625d4255b0338e8b9acc08b6a6a5d02da656795
Reviewed-on: https://cue.gerrithub.io/c/cue-lang/cue/+/1235754
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>