Create `formatting-stack.classpath-linter`

[vemv]

Context

There are 3 sets of defaults: defaults, branch-formatter, project-formatter.

None of those can lint clj nses beyond a given project, e.g. reachable through the classpath.

That's generally reasonable (one doesn't want to lint 3rd-party code), but now the new formatting-stack.linters.one-resource-per-ns linter would maximise its usefulness by linting these nses.

Task

• Create formatting-stack.classpath-linter, analog to project-formatter
  • but with a classpath-wide scope
  • should only lint, not format
  • should only run formatting-stack.linters.one-resource-per-ns
    • No much point in a broader linting for 3rd party code
• Create a strategy that traverses clj namespaces recursively
  • project namespaces -> namespaces from our deps -> namespaces from transitive deps -> ...

Acceptance criteria

One can catch this specific instance:

'("jar:file:/Users/vemv/.m2/repository/clojure-future-spec/clojure-future-spec/1.9.0-beta4/clojure-future-spec-1.9.0-beta4.jar!/clojure/core/specs/alpha.clj"
  "jar:file:/Users/vemv/.m2/repository/org/clojure/core.specs.alpha/0.2.44/core.specs.alpha-0.2.44.jar!/clojure/core/specs/alpha.clj")

Additional resources

#112