Update Source 2 Engine index with related games and logo

Added related games and logo to Source 2 Engine documentation.

Signed-off-by: Gabriel Lima Lopes <135924740+piratabrasileiro1@users.noreply.github.com>

Author: piratabrasileiro1

topics/source-2-engine/index.md

@@ -2,7 +2,8 @@
 display_name: Source 2 Engine
 short_description: Source 2 is a 2015 engine created by valve.
 aliases: source-2,source2
-related: half-life-alyx
+related: half-life-alyx,dota-2,steamvr
 topic: source-2-engine
+logo: source-2-engine.png
 ---
-Source 2 is a 2015 engine created by valve for half-life alyx and counter-strike.
+Source 2 is a 2015 engine created by valve for half-life alyx and counter-strike.