Fix error message about stacks

Description

Problem: currently when I use print e.g. with %[1] (reference to the second element on stack) when stack has only one element in total, I get

InvalidStackReference: reference is out of the stack:
StackRef 1 >= StackSize 1 on stack [...]

error. apparently this >= is wrong since references are 0-based.

Solution: replace >= with >.

Related issue(s)

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