mention IQM loader in Fileformats.md (#5560)

Co-authored-by: Kim Kulling <[email protected]>

doc/Fileformats.md

@@ -28,6 +28,7 @@ __Importers__:
   + KHR_texture_transform ( 5.1 under test )
 - HMB
 - IFC-STEP
+- IQM
 - IRR / IRRMESH
 - [LWO](https://en.wikipedia.org/wiki/LightWave_3D)
 - LWS