I agree that hot key discoverability could be better, but I don't think this is an issue in the PostgreSQL documentation; it's something the browser should handle. The job of the HTML markup is to declare the key -- then it's up to the browser how to present it. Otherwise, every single web page in the world (well, those with hot keys) would have to repeat this analysis, which seems on the wrong level to me.
I agree that that's a thing that browsers should be doing, but presently none are (as far as I know), and the history of web development has many examples of websites having to write crutches for deficient browsers so that their users can have a decent experience, with the definition of decent experience shifting over time.
Attached is a patch to add the nav- tags to the header (could just as easily have done the footer) for up/down/left/right and the javascript to find those ids and simulate a click. I've tested this on chrome (where accesskeys work with alt+ ) and firefox (where accesskeys don't seem to work at all) and it works as expected in both places. The javascript itself is rather naive, but serves as a starting point for discussion.
In researching accesskey, I've noticed that the accesskey="t" stylesheet section doesn't get rendered in our html anywhere. Was "t" = "table of contents"? Seems like something we could delete until we need it again.
