command: export rotation parameter

For completeness.

DOCS/man/en/input.rst

@@ -925,6 +925,9 @@ Property list
     ``video-params/chroma-location``
         Chroma location as string. (Exact values subject to change.)
 
+    ``video-params/rotate``
+        Intended display rotation in degrees (clockwise).
+
     When querying the property with the client API using ``MPV_FORMAT_NODE``,
     or with Lua ``mp.get_property_native``, this will return a mpv_node with
     the following contents:
@@ -943,6 +946,7 @@ Property list
                 "colormatrix"       MPV_FORMAT_STRING
                 "colorlevels"       MPV_FORMAT_STRING
                 "chroma-location"   MPV_FORMAT_STRING
+                "rotate"            MPV_FORMAT_INT64
 
 ``dwidth``, ``dheight``
     Video display size. This is the video size after filters and aspect scaling

player/command.c

@@ -1789,6 +1789,7 @@ static int property_imgparams(struct mp_image_params p, int action, void *arg)
         {"colormatrix",     SUB_PROP_STR(mp_csp_names[p.colorspace])},
         {"colorlevels",     SUB_PROP_STR(mp_csp_levels_names[p.colorlevels])},
         {"chroma-location", SUB_PROP_STR(mp_chroma_names[p.chroma_location])},
+        {"rotate",          SUB_PROP_INT(p.rotate)},
         {0}
     };