tranlon in axis_utils2 returns erroneous istrt value when no elements are moved

[J-Lentz]

Describe the bug
tranlon's Doxygen comment states: The first istrt-1 entries are moved to the end of the array

But in the case where no elements are moved, tranlon sets istrt to 0, rather than the expected value of 1.

To Reproduce

real :: lon(5) = [1., 2., 3., 4., 5.]
real, parameter :: lon_start = 0.
integer :: istrt

call tranlon(lon, lon_start, istrt)
print "(A)", "istrt=" // string(istrt)

Expected behavior
istrt=1

Additional context
If changing the behavior would break users' code, then it could be argued that the inconsistent istrt=0 return value is acceptable and that the error lies in the Doxygen comment.

[rem1776]

fixed with #1172

[J-Lentz]

PR #1172 didn't really fix this, except superficially by commenting out the relevant test case.

The question that I don't know the answer to is: do we fix the bug (which could potentially break users' code, since tranlon is a public procedure), or do we crystallize it into the expected behavior by describing it in the Doxygen comment?

[uramirez8707]

@J-Lentz I think you should update the documentation for this corner case.