Anchor on a specific attribute

Feature request originally from @joshspicer

eg: send https://containers.dev/implementors/json_reference/#remoteEnv , which anchors the screen on the remoteEnv attribute

I manually added links to make each header clickable (i.e. https://containers.dev/implementors/json_reference/#image-specific) - it seems making these individual attributes into links is possible but would be quite time-consuming (there are many attributes, need to make each one into a unique link).