List IRCd versions on "Supported" columns

[DanielOaks]

On things like the ISUPPORT, CAP, etc pages, specific keys and the amount of support they have can raise questions about what software is actually using them.

When people hover or click onto the supported column, it would be nice to bring down a list representing the IRCds that actually advertise that token. Mostly, because doing it that way doesn't risk leaking a raw list of network names.

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This is also useful for tracking down which IRCd advertises a custom ISUPPORT token (one not specified anywhere), whether any other IRCds use it, stuff like that.