Enable either mode will make eldoc display documentation on a popup childframe. The difference is the position of the childframe — the first minor mode displays the childframe on the (left or right) upper corner, while the second displays the childframe right below point.
Note that =eldoc-box-hover-at-point-mode= enables =eldoc-box-hover-mode= — it just adds some more configuration on top of the latter, so you want to disable “at-point” mode before switching to =eldoc-box-hover-mode=.
- =eldoc-box-body= :: Adjust =:background= and =:font= of this face for background color and font of the childframe. I suggest to use a nice Sans Serif font, such as Source Sans Pro.
- =eldoc-box-only-multi-line= :: Set this to non-nil and eldoc-box only display multi-line message in childframe. One line messages are left in minibuffer.
- =eldoc-box-cleanup-interval= :: After this amount of seconds will eldoc-box attempt to cleanup the childframe. E.g. if it is set to 1, the childframe is cleared 1 second after you moved the point to somewhere else (that doesn't have a doc to show). This doesn't apply to =eldoc-box-hover-at-point-mode=, in that mode the childframe is cleared as soon as point moves.
If all you need is a "help at point" popup to be used with eglot, here is my hack. You don't need to enable any minor mode, just call this command on the symbol. (In fact, I don’t even use =eldoc-box-hover-mode= anymore. I bind this hack to =C-h C-h= and lived happily ever after.)