Add mention of textureMirroring property to docs

Change-Id: Ibe5adb23d757e0a7fca9e9ac7bf6bb31418b3056
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>

src/imports/qtcanvas3d/canvastextureprovider.cpp

@@ -135,7 +135,9 @@ CanvasTextureProvider::~CanvasTextureProvider()
  *
  * \note Qt Quick uses texture coordinates where the origin is at top left corner, which is
  * different from OpenGL default coordinate system, where the origin is at bottom left corner.
- * You need to account for this when specifying the UV mapping for the texture.
+ * You need to account for this when specifying the UV mapping for the texture. Alternatively,
+ * you can specify a suitable \l{ShaderEffectSource::textureMirroring}{textureMirroring}
+ * value for your layer or ShaderEffectSource item.
  */
 QJSValue CanvasTextureProvider::createTextureFromSource(QQuickItem *source)
 {