Display invisible entry text at point when visiting a task from the agenda

* lisp/org-agenda.el (org-agenda-goto): Display invisible entry text
* lisp/org-agenda.el (org-agenda-switch-to): Display invisible entry text

Visiting clock lines with RET or TAB in the agenda can put point on a
folded clock drawer.  This means you are editing invisible/hidden text
inside the task entry.  Now when moving to invisible regions show the
entry so point is always visible.

lisp/org-agenda.el

@@ -6486,7 +6486,9 @@ and by additional input from the age of a schedules or deadline entry."
       (org-show-context 'agenda)
       (save-excursion
 	(and (outline-next-heading)
-	     (org-flag-heading nil)))) ; show the next heading
+	     (org-flag-heading nil))))	; show the next heading
+    (when (outline-invisible-p)
+      (show-entry))			; display invisible text
     (recenter (/ (window-height) 2))
     (run-hooks 'org-agenda-after-show-hook)
     (and highlight (org-highlight (point-at-bol) (point-at-eol)))))
@@ -6672,7 +6674,9 @@ at the text of the entry itself."
 	(org-show-context 'agenda)
 	(save-excursion
 	  (and (outline-next-heading)
-	       (org-flag-heading nil)))))))  ; show the next heading
+	       (org-flag-heading nil))) ; show the next heading
+	(when (outline-invisible-p)
+	  (show-entry))))))		; display invisible text
 
 (defun org-agenda-goto-mouse (ev)
   "Go to the Org-mode file which contains the item at the mouse click."