DOC: Cross-reference gdalwarp -te with gdal.WarpOptions outputBounds

[sidhansu10]

This PR improves documentation clarity by explicitly cross-referencing the -te option of gdalwarp with the corresponding Python API parameter outputBounds in gdal.WarpOptions.This helps users map CLI usage to the Python utilities API.
No functional changes.

[rouault]

I'd be a bit hesitant to include information about Python bindings in the help message of the command line utilities. I would rather see the reverse.
And I would note that the new "gdal" command line utilities have now a 1:1 matching between the arguments in the command line and in the Python API, so I'm not too sure if there's much value in documenting the past

[sidhansu10]

I agree that documenting Python bindings inside the CLI utility docs may not be the best direction. I’m happy to rework this so that the cross-reference lives on the Python side instead (e.g. in gdal.WarpOptions / Python utilities docs), pointing back to the corresponding CLI option.
If that sounds preferable, I can:

1. remove the Python reference from the gdalwarp CLI docs, and
2. add a short note in the Python API documentation mentioning the equivalent -te CLI option.
   Please let me know if that direction would be more acceptable, or if you’d prefer this to target only the new gdal CLI instead.

[coveralls]

coverage: 71.521% (-0.01%) from 71.534%
when pulling a50c5ca on sidhansu10:doc-warp-te-python-crossref
into 07547f7 on OSGeo:master.