Fix a couple small "code" bugs

[d-torrance]

We fix two little code bugs I noticed:

First, we previously assumed that the given FilePosition object would include a stopping position, which isn't the case for some things (like outputs of locate(DocumentTag):

i1 : locate makeDocumentTag (ideal, List)

o1 = /usr/share/Macaulay2/Macaulay2Doc/functions/ideal-doc.m2:42:0

o1 : FilePosition

i2 : code oo
stdio:2:4:(3): error: array index 3 out of bounds 0 .. 2

So we assume that the stopping is the same as the starting position, which maybe isn't great, but at least there's no more error:

i1 : locate makeDocumentTag (ideal, List)

o1 = src/macaulay2/M2/M2/Macaulay2/packages/Macaulay2Doc/functions/ideal-doc.m2:42:0

o1 : FilePosition

i2 : code oo

o2 = src/macaulay2/M2/M2/Macaulay2/packages/Macaulay2Doc/functions/ideal-doc.m2:42:0: --source code:
     document { 

The other bug is very very minor. Suppose, for some crazy reason, we write some Macaulay2 code in a file named something that matches the regex "startup.m2.in$", e.g., "startupxm2xin". If we load it and call code on something from it, then it will give us something from the actual startup.m2.in:

i1 : get "startupxm2xin"

o1 = f = x -> x^2

i2 : load "startupxm2xin"

i3 : code f

o3 = startupxm2xin:1:4-1:12: --source code:
     -- -*- coding: utf-8 -*-

If we properly escape the dots, then it works as expected:

i3 : code f

o3 = startupxm2xin:1:4-1:12: --source code:
     f = x -> x^2

[mahrud]

The second bug is actually hilarious 😂