mu4e-view: remove overlays before erasing

erase-buffer is not enough, and [1][2] can stay behind in the buffer.

mu4e/mu4e-view-common.el

@@ -549,6 +549,7 @@ Also number them so they can be opened using `mu4e-view-go-to-url'."
                       keymap ,mu4e-view-active-urls-keymap
                       help-echo
                       "[mouse-1] or [M-RET] to open the link"))
+              (overlay-put ov 'mu4e-overlay t)
               (overlay-put ov 'after-string
                            (propertize (format "\u200B[%d]" num)
                                        'face 'mu4e-url-number-face)))))))))

mu4e/mu4e-view-gnus.el

@@ -54,6 +54,7 @@
     (kill-buffer gnus-article-buffer))
   (with-current-buffer (get-buffer-create gnus-article-buffer)
     (let ((inhibit-read-only t))
+      (remove-overlays (point-min) (point-max) 'mu4e-overlay t)
       (erase-buffer)
       (insert-file-contents-literally
        (mu4e-message-field msg :path) nil nil nil t)))