Add max_result_dimension processing option docs

Author: DarthSim

docs/usage/processing.mdx

@@ -1134,6 +1134,19 @@ Allows redefining [IMGPROXY_MAX_ANIMATION_FRAME_RESOLUTION](../configuration/opt
 Since this option allows redefining a security restriction, its usage is not allowed unless the [IMGPROXY_ALLOW_SECURITY_OPTIONS](../configuration/options.mdx#IMGPROXY_ALLOW_SECURITY_OPTIONS) config is set to `true`.
 :::
 
+### Max result dimension
+
+```imgproxy_url_option
+max_result_dimension:%size
+mrd:%size
+```
+
+Allows redefining [IMGPROXY_MAX_RESULT_DIMENSION](../configuration/options.mdx#IMGPROXY_MAX_RESULT_DIMENSION) config.
+
+:::warning
+Since this option allows redefining a security restriction, its usage is not allowed unless the [IMGPROXY_ALLOW_SECURITY_OPTIONS](../configuration/options.mdx#IMGPROXY_ALLOW_SECURITY_OPTIONS) config is set to `true`.
+:::
+
 ## Source URL
 ### Plain