[czj]

A name .super-slim.yml misspells is ignored. LineLenght: {max: 150} leaves the limit at 120, Instancevariables: {enabled: false} leaves the rule on, formatter: {max_line_length: 120} wraps nothing, and super-slim lint exits 0 without a word: the file reads as if it were applied. The linter already reports a rule name it doesn't know in a super-slim:disable comment.

Unknown names now stop lint and format with a usage error that names them and lists what the file can hold there. This turns a configuration that was read without complaint into an error, which is why this pull request does not merge itself: it wants a decision, and a line under Breaking in the changelog if it goes in.

• Rules: a key of linters: that is no rule of super-slim lint, in the words of the directive's offense.
• Options of a rule: anything but the rule's own options, include and exclude; preset only on the rules that have one.
• Settings: a top-level key other than linters, format, fmt and tailwind_classes, and under format: anything but max_line_length and attribute_delimiters.
• Who it stops: a file carrying a rule from slim-lint that SuperSlim never had, such as RuboCop: or Tag:, would fail until the entry is removed.

Proof

Each .super-slim.yml below passes super-slim lint on main with no output and status 0, but the one with preset, which main answers with LineLength: unknown preset `bootstrap5`, use one of: and an empty list. With this change, status 64 and:

.super-slim.yml	Message
linters: {LineLenght: {max: 150}}	.super-slim.yml: `LineLenght` is not a rule of super-slim lint
linters: {LineLength: {maximum: 150}}	.super-slim.yml: `maximum` is not an option of LineLength, use one of: enabled, max, include, exclude
linters: {LineLength: {preset: bootstrap5}}	.super-slim.yml: `preset` is not an option of LineLength, use one of: enabled, max, include, exclude
formatter: {max_line_length: 120}	.super-slim.yml: `formatter` is not a setting, use one of: linters, format, fmt, tailwind_classes
format: {line_length: 120}	.super-slim.yml: `line_length` is not a setting of `format`, use one of: max_line_length, attribute_delimiters

test/cli_test.rb holds the five; the README's paragraph on the configuration file says so.