Alternatively: The Register Update

The Highlights

• The register has been completely overhauled, and now acts as a hybrid between the current functionality of the register and the global array from Vyxal 2. Essentially a global stack shared across all contexts, the register can now store multiple items and can have functions applied to it.
• Lots of parity updates with elements from Vyxal 2 and Vyxal 3 legacy
• Minor bugfixes, documentation changes, and behind the scenes stuff

What's New

• #D is dictionary decompress
• ∆p is prime factors
• ∆- is negative 1 power, bypassing some dyadic weirdness with using *
• • Now does "string extend to length" which repeats the shorter string until it is the length of the longer one
• • also does vectorised pair (welcome back multi-command)
• ⊢ returns truthy indices after applying a function
• ∻ does string vertical merge
• k/ pushes /\
• k⍾ two bytes saved on amogus
• Þe and ÞE enumerate args, 0 and 1-indexed respectively
• ↻ returns the length of iterate-while-unique
• c returns the length of scan-fixpoint
• ` now pops from the register
• A ton of register operations, check element documentation for more

What's Changed

• Apply at head properly works now
• Q works with reversed inputs
• ↺ now actually returns the list
• `#`` is now stack length

This includes contributions from @pacmanboss256, and thanks to @lyxal and @ysthakur for register help.

I (pacman) am back at college now so this is likely the last major update for a while.