Change scan example scanning variable

[timothy-nunn]

Do we know how close the solution is initially to this inboard leg limit? Would it be better to have a scan example that directly changes a variable instead of a limit?

Originally posted by @chris-ashe in #3947 (comment)

The current scan example is a bit confusing and often does not produce very interesting plots. It is scanning the bound of a constraint and therefore if that constraint is not limiting the solution then the scan graphs are flat. I'm sure modellers in the group will be able to provide more interesting and meaningful scan examples.