removed sample_code stub from appendix/index.html (rst content remains, but is unreferenced)
removed sample_code stub from appendix/index.html (rst content remains, but is unreferenced)

saupchurch/schemas,diekhans/ga4gh-schemas,macieksmuga/schemas,ga4gh/ga4gh-schemas,diekhans/ga4gh-schemas,heuermh/ga4gh-schemas,ga4gh/schemas,dcolligan/schemas,pcingola/schemas