PTPN22 and rheumatoid arthritis: The novel associations at PRL and NFIA add to the list of suggestive or confirmed anti‐CCP–negative RA susceptibility loci: PTPN22, TNFAIP3, C5orf30, STAT4, BLK8, SPP116, CLEC16A17, IRF518, DCIR19, 20, CLYBL14, SMIM2114, and ANKRD5521.