minor adjustment for load_transcripts function

[Huangy57]

This pull request introduces two minor changes to the genescores.py script:

1. Added case-insensitive Check for 'chr' Prefix: Ensured that chromosome names are consistently prefixed with 'chr' by checking in a case-insensitive manner and adding the prefix if necessary.
2. Added print statement for missing transcripts: Implemented a print statement to notify users when a transcript could not be found in the database, aiding in debugging.