Adjust wording of "The only constraint is you can never change the type associated with a tag number"

[bernardnormier]

The only constraint is you can never change the type associated with a tag number

I find this advice misleading, the rule should be never to reuse tag numbers because even if the type is the same, would > be unwise to reuse the tag for a new parameter of the same type.

Reusing the tag number with a parameter of the same type doesn't break the on-the-wire contract, but it breaks the
application contract.

Originally posted by @pepone in #205 (comment)