sdbusplus: use shorter type aliases

The sdbusplus headers provide shortened aliases for many types.
Switch to using them to provide better code clarity and shorter
lines.  Possible replacements are for:
  * bus_t
  * exception_t
  * manager_t
  * match_t
  * message_t
  * object_t
  * slot_t

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I91502c85799b7d3be22b7d05659ff26bea08c32b
diff --git a/src/main.cpp b/src/main.cpp
index 5b5341d..90c189d 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -43,8 +43,8 @@
     EventPtr eventP{event};
     event = nullptr;
 
-    sdbusplus::bus::bus bus = sdbusplus::bus::new_default();
-    sdbusplus::server::manager::manager objManager{
+    sdbusplus::bus_t bus = sdbusplus::bus::new_default();
+    sdbusplus::server::manager_t objManager{
         bus, "/xyz/openbmc_project/Chassis/Buttons"};
 
     bus.request_name("xyz.openbmc_project.Chassis.Buttons");