Incorrect code location for functions defined in standard input

[d-torrance]

Since #3403:

i1 : f = x -> x^2

o1 = f

o1 : FunctionClosure

i2 : code f

o2 = stdio:1:6-1:11: --source code:
     -- This is the beginning of your Macaulay2 log stored at /home/profzoom/.Macaulay2/history.m2

I suppose the solution would be to keep track of how long the history is when we start M2 and add that to the line number when finding the code.

[mahrud]

Ah yes I should have noticed this from the getHistory lines in code.m2.

[mahrud]

This is actually more complicated than I expected. I added a call to where_history in this commit, but:

1. it seems to return zero if it's called before the first prompt, even if it's after readHistory apparently!
2. it seems to be off by an inconsistent number (up to 4 even) from the right number to get code working in your example.

I'm not sure if I have time to debug this. We can disable history if this is too complicated to resolve.

[d-torrance]

I think I figured it out -- see #3416.

[d-torrance]

Closed by #3416