Merge pull request #36371 from Calinou/doc-improve-panoramasky

Improve the PanoramaSky class documentation

doc/classes/PanoramaSky.xml

@@ -5,6 +5,8 @@
 	</brief_description>
 	<description>
 		A resource referenced in an [Environment] that is used to draw a background. The Panorama sky functions similar to skyboxes in other engines, except it uses an equirectangular sky map instead of a cube map.
+		Using an HDR panorama is strongly recommended for accurate, high-quality reflections. Godot supports the Radiance HDR ([code].hdr[/code]) and OpenEXR ([code].exr[/code]) image formats for this purpose.
+		You can use [url=https://danilw.github.io/GLSL-howto/cubemap_to_panorama_js/cubemap_to_panorama.html]this tool[/url] to convert a cube map to an equirectangular sky map.
 	</description>
 	<tutorials>
 	</tutorials>