Fix void-function: pdf-tools-install-noverify

For folks who try `M-x pdf-tools-install` at startup instead of simply
loading a pdf file.

modules/tools/pdf/config.el

@@ -53,6 +53,7 @@
   (setq-hook! 'pdf-view-mode-hook evil-normal-state-cursor (list nil))
 
   ;; Install epdfinfo binary if needed, blocking until it is finished
+  (require 'pdf-tools)
   (unless (file-executable-p pdf-info-epdfinfo-program)
     (let ((wconf (current-window-configuration)))
       (pdf-tools-install)