Minor changes in Planner, Controller, Smoother, Route and Behaviour Servers in Navigation Concepts (#700)

Changed from Four to Five in representing action servers.

Signed-off-by: YASVANTH S <83586632+Yasvanth-S@users.noreply.github.com>

Author: Yasvanth-S

concepts/index.rst

@@ -110,7 +110,7 @@ In this section, the general concepts around them and their uses in this project
 Planner, Controller, Smoother, Route, and Behavior Servers
 ==========================================================
 
-Four of the action servers in this project are the planner, behavior, smoother, route, and controller servers.
+Five of the action servers in this project are the planner, behavior, smoother, route, and controller servers.
 
 These action servers are used to host a map of algorithm plugins to complete various tasks.
 They also host the environmental representation used by the algorithm plugins to compute their outputs.