Minor diagram tweaks

Mostly say 'Composition Engine' rather than 'Crossplane Composition' to
distinguish from the Composition API type.

'Crossplane Composition Engine' won't fit.

Signed-off-by: Nic Cope <[email protected]>

Author: negz

content/v2.0-preview/what-is-crossplane/_index.md

@@ -79,7 +79,7 @@ user(User)
 
 subgraph control [Control Plane]
   api(Application API)
-  controller(Your Application Controller)
+  controller[Your Application Controller]
   deployment(Deployment API)
   service(Service API)
 end
@@ -103,7 +103,7 @@ user(User)
 subgraph control [Control Plane]
   api(Application API)
 
-  subgraph crossplane [Crossplane Composition]
+  subgraph crossplane [Composition Engine]
     fn(Python Function)
   end
 
@@ -159,7 +159,7 @@ user(User)
 
 subgraph control [Control Plane]
   instance(RDS Instance API)
-  controller(Crossplane MR Controller)
+  controller(Managed Resource Controller)
 end
 
 subgraph aws [Amazon Web Services]
@@ -183,15 +183,15 @@ user(User)
 subgraph control [Control Plane]
   api(Application API)
 
-  subgraph crossplane [Crossplane Composition]
+  subgraph crossplane [Composition Engine]
     fn(Python Function)
   end
 
   deployment(Deployment API)
   service(Service API)
   instance(RDS Instance API)
 
-  controller(Crossplane MR Controller)
+  controller(Managed Resource Controller)
 end
 
 subgraph aws [Amazon Web Services]