Abstract bindings for site help and add for keyboard

         cookies.set('rhythm', 'on')
       }
     } else if (ev.key == 'f') showKeyboardFollowLinks() // f   show "follow links"
+    else if (ev.key == '?') goHelp()                    // ?   show help
     else if (ev.key == 'h') goBack()                    // h   go back
     else if (ev.key == 'j') scrollDown()                // j   scroll down 3 EMs
     else if (ev.key == 'k') scrollUp()                  // k   scroll up 3 EMs

 
 const em = parseFloat(getComputedStyle(document.documentElement).fontSize)
 
+const goHelp = () => { go('/help') }
 const goHome = () => { go(document.querySelector("a[rel=home]").href) }
 const goUp = () => { go(document.querySelector("a[rel=up]").href) }
 const goPrevious = () => { go(document.querySelector("a[rel=prev]").href) }

       partialContainer.innerHTML = ''
       return
     }
-    if (input == 'help') {                           // help
-      go('/help')
-    } else if (input.startsWith('query for')) {      // query for
+    if (input == 'help') goHelp()                    // help
+    else if (input.startsWith('query for')) {      // query for
       const query = input.slice(10)
       go(`/search?q=$${query}`)
     } else if (input.startsWith('go')) {             // go