Allow forward slashes in vendor definition token types

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This merge request lets a vendor definition carry a detection rule id that contains a forward slash, i.e. /.

Related to #631759.

Gap

• token_type must equal the rule id, because the registry is keyed by it.
• TOKEN_TYPE_PATTERN does not allow forward slashes, so it rejects rule ids such as Hashicorp Terraform user/org API token.
• A definition for such a rule needs a renamed token_type and a hand-edited registry key, as in !259344 (merged).

Fix

• We add the forward slash to TOKEN_TYPE_PATTERN regex.
• This is safe: token_type reaches generated source only in the registry entry, through #inspect.

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