Fix lsp-ui-doc-glance auto-hide

Fixes #695

For some inexplicable reason, `lsp-ui-doc-show` calls
`lsp-ui-doc--callback` synchronously, while `lsp-ui-doc-glance` went via
a more tortuous asynchronous route (via `lsp-ui-doc--make-request`).

This commit makes `lsp-ui-doc-glance` equivalent to calling
`lsp-ui-doc-show` followed by *delayed* addition to `post-command-hook`
(since we're already in a command) of the
`lsp-ui-doc--glance-hide-frame` function.

Note that `lsp-ui-doc--glance-hide-frame` is also simplified to just
remove itself from `post-command-hook` and directly call
`lsp-ui-doc-hide`.

Author: Lenbok

lsp-ui-doc.el

@@ -1164,25 +1164,18 @@ It is supposed to be called from `lsp-ui--toggle'"
   (interactive)
   (lsp-ui-doc--hide-frame))
 
-(defvar-local lsp-ui-doc--unfocus-frame-timer nil)
 (defun lsp-ui-doc--glance-hide-frame ()
-  "Hook to hide hover information popup for `lsp-ui-doc-glance'."
-  (when (or (overlayp lsp-ui-doc--inline-ov)
-            (lsp-ui-doc--frame-visible-p))
-    (lsp-ui-doc--hide-frame)
-    (remove-hook 'post-command-hook 'lsp-ui-doc--glance-hide-frame)
-    ;; make sure child frame is unfocused
-    (setq lsp-ui-doc--unfocus-frame-timer
-          (run-at-time 1 nil #'lsp-ui-doc-unfocus-frame))))
+  "Hook function for auto-hiding hover information popup for `lsp-ui-doc-glance'."
+  (remove-hook 'post-command-hook 'lsp-ui-doc--glance-hide-frame)
+  (lsp-ui-doc--hide-frame))
 
 (defun lsp-ui-doc-glance ()
   "Trigger display hover information popup and hide it on next typing."
   (interactive)
-  (let ((lsp-ui-doc-show-with-cursor t))
-    (lsp-ui-doc--make-request))
-  (when lsp-ui-doc--unfocus-frame-timer
-    (cancel-timer lsp-ui-doc--unfocus-frame-timer))
-  (add-hook 'post-command-hook 'lsp-ui-doc--glance-hide-frame))
+  (lsp-ui-doc-show)
+  (run-at-time 1 nil
+               (lambda ()
+                 (add-hook 'post-command-hook 'lsp-ui-doc--glance-hide-frame))))
 
 (define-minor-mode lsp-ui-doc-frame-mode
   "Marker mode to add additional key bind for lsp-ui-doc-frame."