Fixed GitHub edit links

`https://github.com/RNAcentral/rnacentral-webcode/edit/django/rnacentral/portal/templates/portal/docs/api-v1.md`
--> 
`https://github.com/RNAcentral/rnacentral-webcode/edit/release/1.0/rnacentral/portal/templates/portal/docs/api-v1.md`

etc.