feat: add warning to scripts/port_status.py (#17132)
Adds some warnings about work that needs to be done to keep tracking of porting, e.g.
```
# The following files are marked as ported, but do not have a SYNCHRONIZED WITH MATHLIB4 label.
logic.is_empty
data.fin.fin2
data.sigma.basic
# The following files are marked as ported, but have not been verified against a commit hash from mathlib.
logic.is_empty
data.fin.fin2
algebra.abs
algebra.covariant_and_contravariant
algebra.group.basic
algebra.group.defs
# The following files have been modified since the commit at which they were verified.
logic.relator
```
Co-authored-by: Scott Morrison <scott.morrison@gmail.com>
