fix build error from duplicate bibkeys

[danielgildea]

also, fix python warning from string escapes

[github-actions[bot]]

Build successful. Some useful links:

• Complete site preview: https://preview.aclanthology.org/fix-dup-bibkey
• Potential volumes of interest: 2024.jeptalnrecital-jep, 2024.jeptalnrecital-taln, 2024.jeptalnrecital-trad, 2024.jeptalnrecital-recital, 2024.jeptalnrecital-deft, 2024.tacl-1

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