Clarify VERSION_DISCLAIMER in `src/clients/tldr.rs`

Context: When using navi --tldr <cmd>.

The error message in this snippet needs clarification: https://github.com/denisidoro/navi/blob/f7330b9ad5bd95b7d1a3c96d00e0a77deb589147/src/clients/tldr.rs#L10-L12

The message suggests using TLDR tealdeer, but it doesn't mention that the client.tealdeer: true configuration is a requirement for it to work (see https://github.com/denisidoro/navi/pull/873 and https://github.com/denisidoro/navi/issues/902#issuecomment-2263011184).

Without this requirement, the message feels confusing. Even after adding tealdeer to the system, navi --tldr <cmd> still doesn't work and displays the same message.

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I found tealdeer at a different GitHub repository address: https://github.com/tealdeer-rs/tealdeer

It looks like tealdeer has migrated to a dedicated repository. This could be updated in the snippet message as well.