Add setting for tooltips show delay.

minetest.conf.example

@@ -200,6 +200,8 @@
 #repeat_rightclick_time = 0.25
 # Make fog and sky colors depend on daytime (dawn/sunset) and view direction
 #directional_colored_fog = true
+#tooltip_show_delay = 400
+# Delay showing tooltips, in miliseconds
 
 # Default timeout for cURL, in milliseconds
 # Only has an effect if compiled with cURL