Change Prompt to Avoid Incorrect Information for PubMed Central Sources

[cannin]

Currently, the LLM context does not have author or journal information available for PMC sources. The LLM tries to accommodate the user using names it finds in the text (e.g., authors of references cited by the source). This causes mismatches such as article authors and cited PMC sources in reports. The commit allows the LLM to provide a simpler but often more correct citation with just title and link.