Major BIP 360 Update

The term "P2TR-" is introduced as a descriptor for a specific output type related to taproot, with the key path element removed. This naming convention is not only self-explanatory but also sets accurate expectations by indicating that it retains most functionalities of P2TR albeit not all. The use of the minus sign in "P2TR-" is strategic, signaling that something is missing from the standard P2TR configuration. For individuals who are already familiar with taproot, this nomenclature approach offers an intuitive understanding without necessitating additional learning. Essentially, "P2TR-" serves as a straightforward and effective way to communicate the modified capabilities of this particular taproot variant.