Modified the descriptions for CollisionPolygon2D and created descriptions for CollisionPolygon

doc/classes/CollisionPolygon.xml

@@ -1,8 +1,10 @@
 <?xml version="1.0" encoding="UTF-8" ?>
 <class name="CollisionPolygon" inherits="Spatial" category="Core" version="3.0.alpha.custom_build">
 	<brief_description>
+		Editor-only class for defining a collision polygon in 3D space.
 	</brief_description>
 	<description>
+		Allows editing a collision polygon's vertices on a selected plane. Can also set a depth perpendicular to that plane. This class is only available in the editor. It will not appear in the scene tree at runtime. Creates a [Shape] for gameplay. Properties modified during gameplay will have no effect.
 	</description>
 	<tutorials>
 	</tutorials>
@@ -54,10 +56,13 @@
 	</methods>
 	<members>
 		<member name="depth" type="float" setter="set_depth" getter="get_depth">
+			Length that the resulting collision extends in either direction perpendicular to its polygon.
 		</member>
 		<member name="disabled" type="bool" setter="set_disabled" getter="is_disabled">
+			If true, no collision will be produced.
 		</member>
 		<member name="polygon" type="PoolVector2Array" setter="set_polygon" getter="get_polygon">
+			Array of vertices which define the polygon.
 		</member>
 	</members>
 	<constants>

doc/classes/CollisionPolygon2D.xml

@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="UTF-8" ?>
 <class name="CollisionPolygon2D" inherits="Node2D" category="Core" version="3.0.alpha.custom_build">
 	<brief_description>
-		Editor-only class for easy editing of collision polygons.
+		Editor-only class for defining a collision polygon in 2D space.
 	</brief_description>
 	<description>
-		Editor-only class. This is not present when running the game. It's used in the editor to properly edit and position collision shapes in [CollisionObject2D]. This is not accessible from regular code. This class is for editing custom shape polygons.
+		Allows editing a collision polygon's vertices. This class is only available in the editor. It will not appear in the scene tree at runtime. Creates a [Shape2D] for gameplay. Properties modified during gameplay will have no effect.
 	</description>
 	<tutorials>
 	</tutorials>
@@ -75,12 +75,16 @@
 	</methods>
 	<members>
 		<member name="build_mode" type="int" setter="set_build_mode" getter="get_build_mode" enum="CollisionPolygon2D.BuildMode">
+			If BUILD_SOLIDS, the polygon and the area within it will have collision. If BUILD_SEGMENTS, only the edges of the polygon will have collision.
 		</member>
 		<member name="disabled" type="bool" setter="set_disabled" getter="is_disabled">
+			If true, no collision will be produced.
 		</member>
 		<member name="one_way_collision" type="bool" setter="set_one_way_collision" getter="is_one_way_collision_enabled">
+			If true, only edges that face up, relative to CollisionPolygon2D's rotation, will collide with other objects.
 		</member>
 		<member name="polygon" type="PoolVector2Array" setter="set_polygon" getter="get_polygon">
+			Array of vertices which define the polygon.
 		</member>
 	</members>
 	<constants>