fix replacement key for deprecated option display.height

replacement key for deprecated option `display.height` was set to `display.height` itself. I believe it should be `display.max_rows` instead.

This avoid a weird message in `describe_option()` :

    display.height: [default: 60] [currently: 60]
    : int
            Deprecated.
	    (Deprecated, use `display.height` instead.)

Author: pierre-haessig

pandas/core/config_init.py

@@ -252,7 +252,7 @@ def mpl_style_cb(key):
 
 cf.deprecate_option('display.height',
                     msg=pc_height_deprecation_warning,
-                    rkey='display.height')
+                    rkey='display.max_rows')
 
 tc_sim_interactive_doc = """
 : boolean