feat(#108): @ must be at top level

[Marat-Tim]

I'm not sure we can rely on the order of objects within a single tag, or that using @ in inner objects will always result in an element with base='$.@'
But if that’s not guaranteed, it seems like implementing this lint may not be possible

[github-actions]

🚀 Performance Analysis

All benchmarks are within the acceptable range. No critical degradation detected (threshold is 100%). Please refer to the detailed report for more information.

Click to see the detailed report

Test	Base Score	PR Score	Change	% Change	Unit	Mode
benchmarks.SourceBench.scansXmir (size=S)	5794.153	5921.028	126.875	2.19%	ms/op	Average Time
benchmarks.SourceBench.scansXmir (size=M)	6472.323	6587.806	115.483	1.78%	ms/op	Average Time
benchmarks.SourceBench.scansXmir (size=L)	7563.079	7390.519	-172.560	-2.28%	ms/op	Average Time
benchmarks.SourceBench.scansXmir (size=XL)	8720.330	8697.317	-23.013	-0.26%	ms/op	Average Time
benchmarks.SourceBench.scansXmir (size=XXL)	20524.692	20834.010	309.318	1.51%	ms/op	Average Time

⚠️ Performance loss: benchmarks.SourceBench.scansXmir (size=S) is slower by 126.875 ms/op (2.19%)
⚠️ Performance loss: benchmarks.SourceBench.scansXmir (size=M) is slower by 115.483 ms/op (1.78%)
✅ Performance gain: benchmarks.SourceBench.scansXmir (size=L) is faster by 172.560 ms/op (2.28%)
✅ Performance gain: benchmarks.SourceBench.scansXmir (size=XL) is faster by 23.013 ms/op (0.26%)
⚠️ Performance loss: benchmarks.SourceBench.scansXmir (size=XXL) is slower by 309.318 ms/op (1.51%)

[Marat-Tim]

@yegor256

[yegor256]

@Marat-Tim maybe just this:

[] > app
  foo > x
  bar > @

This will better illustrate what you expect users to write.

[Marat-Tim]

@yegor256 I don't get it - the example here is Incorrect, but the code you're suggesting doesn't actually violate rules of this lint

[yegor256]

@h1alexbel please, review this one