Whether a stylesheet is understood well enough to patch.
round_trips is the half that matters for safety: it is what every codemod
checks before touching a file. A stylesheet that round-trips but has
diagnostics is still patchable; one that does not round-trip is not, and
IgniterCss will refuse rather than risk a wrong edit.
errors is the verdict, each placed by line and column: the parser's errors
less the ones it raises against valid CSS, such as a : in a custom
property's value or an @apply with no ; written last in a block.
diagnostics counts what the parser raised before that.
Summary
Types
@type t() :: %IgniterCss.Validation{ diagnostics: non_neg_integer(), errors: [IgniterCss.Diagnostic.t()], message: String.t(), round_trips: boolean(), valid: boolean() }