Improve formulation of PMC in prefix map

In biopragmatics/bioregistry#965, we got authoritative confirmation that PMC local unique identifiers should contain the PMC. Therefore, the following entry in the BioLink prefix map should be updated:

biolink-model/prefix-map/biolink-model-prefix-map.json

Line 147 in d9b97df

"PMC": "http://europepmc.org/articles/PMC",

Interestingly, there is also an adjacent line that doubles PMC prefix with PMCID that has the opposite opinion:

biolink-model/prefix-map/biolink-model-prefix-map.json

Line 148 in d9b97df

"PMCID": "http://www.ncbi.nlm.nih.gov/pmc/",

Oh, nice, this is a duplicate of #1366 and has already been solved by #1402. Cheers