Change direction in wording around stack unwinding

[wucke13]

The original sentence reads:

Taking a branch unwinds the operand stack up to the height where the targeted structured control instruction was entered.

However, usually one speaks of the top of the stack as where new values are pushed to/popped from. Following that metaphor when talking about unwinding, unwinding goes down in the stack. Hence the following proposal:

Taking a branch unwinds the operand stack updown to the height where the targeted structured control instruction was entered.

https://github.com/WebAssembly/spec/blob/bbe955d1fab3d7f74f4e9d19d77df85e482c397f/document/core/syntax/instructions.rst?plain=1#L691C45-L691C48

[rossberg]

The "up to" here is used in the sense of "up to some limit", not suggesting any stack direction.

[wucke13]

Ah I see! I'm wondering if "down to some limit" could not work the same on the semantics side, while adhering to the intuition of a stack. Like, "to a limit" would work as well, but if a direction is provided, why not take the more fitting one given the adjacent metaphor.