slang hover on parameterized enums: per-instance values are unlabeled

In slang-server, hovering a localparam or enum member inside a parameterized module returns one section per elaborated instance. The sections don't say which instance each one belongs to. If you take the first section whose width matches, instances with the same width but different parameter values can show each other's enum values. The safe rule is to accept a value only when every section of that width agrees, and otherwise drop it for all instances. Once the answer no longer depends on which instance asks, a cache keyed by typedef plus width is sound.