fix links

docs/modules/ROOT/pages/jme3/features.adoc

@@ -250,7 +250,7 @@ a|OGG Vorbis music and sounds
 
 == Special Effects
 
-*  xref:jme3/advanced/particle_emitters.adoc[Particles: Smoke, fire, explosions, etc]
+*  xref:core:effect/particle_emitters.adoc[Particles: Smoke, fire, explosions, etc]
 *  xref:core:effect/effects_overview.adoc[Post processing / 2D Filter Effects]
 **  Reflective Water
 **  Shadow mapping

docs/modules/core/pages/effect/effects_overview.adoc

@@ -215,7 +215,7 @@ Thanks for your awesome contributions! Keep them coming!
 image:effect/explosion-5.png[explosion-5.png,width="150",height="100"]
 image:effect/particle.png[particle.png,width="150",height="100"]
 
-xref:jme3/advanced/particle_emitters.adoc[Particle emitter effects] are highly configurable and can have any texture. They can simulate smoke, dust, leaves, meteors, snowflakes, mosquitos, fire, explosions, clusters, embers, sparks…
+xref:effect/particle_emitters.adoc[Particle emitter effects] are highly configurable and can have any texture. They can simulate smoke, dust, leaves, meteors, snowflakes, mosquitos, fire, explosions, clusters, embers, sparks…
 
 *  link:{uri-jmonkeyengine}jme3-examples/src/main/java/jme3test/effect/TestExplosionEffect.java[TestExplosionEffect.java] – debris, flame, flash, shockwave, smoke, sparks.
 *  link:{uri-jmonkeyengine}jme3-examples/src/main/java/jme3test/effect/TestPointSprite.java[TestPointSprite.java] – cluster of points.
@@ -251,6 +251,6 @@ Filters in a nutshell.
 
 See also:
 
-*  xref:jme3/advanced/particle_emitters.adoc[Particle Emitters]
+*  xref:effect/particle_emitters.adoc[Particle Emitters]
 *  xref:jme3/advanced/bloom_and_glow.adoc[Bloom and Glow]
 *  link:http://www.smashingmagazine.com/2008/08/07/50-photoshop-tutorials-for-sky-and-space-effects/[Photoshop Tutorial for Sky and space effects (article)]

docs/modules/tutorials/pages/beginner/hello_effects.adoc

@@ -1,7 +1,6 @@
 = jMonkeyEngine 3 Tutorial (12) - Hello Effects
-:author:
-:revnumber:
-:revdate: 2020/07/06
+:revnumber: 2.0
+:revdate: 2020/07/24
 :keywords: beginner, documentation, intro, transparency, effect
 
 
@@ -261,7 +260,7 @@ a| Whether particles fall down (positive) or fly up (negative). Set to 0f for a
 
 |===
 
-You can find details about xref:ROOT:jme3/advanced/particle_emitters.adoc#configure_parameters[effect parameters] here.
+You can find details about xref:core:effect/particle_emitters.adoc#configure_parameters[effect parameters] here.
 Add and modify one parameter at a time, and try different values until you get the effect you want.
 
 

docs/modules/tutorials/pages/concepts/faq.adoc

@@ -703,7 +703,7 @@ For swarm like effects you use particle emitters.
 *Learn more:*
 
 * xref:beginner/hello_effects.adoc[Hello Effects]
-* xref:ROOT:jme3/advanced/particle_emitters.adoc[Particle Emitters]
+* xref:core:effect/particle_emitters.adoc[Particle Emitters]
 * xref:ROOT:jme3/advanced/bloom_and_glow.adoc[Bloom and Glow]
 * xref:core:effect/effects_overview.adoc[Effects Overview]
 * link:https://github.com/jMonkeyEngine/jmonkeyengine/blob/master/jme3-core/src/main/java/com/jme3/effect/shapes/EmitterSphereShape.java[com.jme3.effect.EmitterSphereShape.java]

docs/modules/tutorials/pages/concepts/math.adoc

@@ -720,7 +720,7 @@ Rectangle defines a finite plane within three dimensional space that is specifie
 
 === jME Usage
 
-Rectangle is a straight forward data class that simply maintains values that defines a Rectangle in 3D space. One interesting use is the `random` method that will create a random point on the Rectangle. The xref:core:effect/effects_overview.adoc[Particle System] makes use of this to define an area that generates xref:ROOT:jme3/advanced/particle_emitters.adoc[Particles].
+Rectangle is a straight forward data class that simply maintains values that defines a Rectangle in 3D space. One interesting use is the `random` method that will create a random point on the Rectangle. The xref:core:effect/effects_overview.adoc[Particle System] makes use of this to define an area that generates xref:core:effect/particle_emitters.adoc[Particles].
 
 
 === Example 1 : Define a Rectangle and Get a Point From It