Change up and down arrows to arrow.u and arrow.d?

[b-vanstraaten]

Currently, the left and right arrows are accessed with the commands "arrow.l" and "arrow.r".

However, up and down arrows are accessed through the commands "arrow.t" and "arrow.b" which I guess refers to top and bottom.

I propose changing the commands to "arrow.u" and "arrow.d" for consistency in name and with latex (https://garsia.math.yorku.ca/MPWP/LATEXmath/node9.html)

[Enivex]

This makes a lot of sense in my opinion. It's also relevant for the harpoon symbols, and perhaps more.

[laurmaedje]

The l, t, b, r convention is used across all of the symbols. Changing that would bring a lot of churn.

[Enivex]

The l, t, b, r convention is used across all of the symbols. Changing that would bring a lot of churn.

It makes perfect sense for many things, but arrows have a direction. An arrow points up or down, not top or bottom.

[b-vanstraaten]

Perhaps we could alias arrow.t with arrow.p so that either would produce the symbol. Likewise with arrow.b and arrow.d?