add CST to docs

Author: zolanaj

docs/src/reopt/inputs.md

@@ -176,3 +176,8 @@ REopt.ElectricHeater
 ```@docs
 REopt.ASHP
 ```
+
+## CST
+```@docs
+REopt.CST
+```

docs/src/reopt/outputs.md

@@ -98,4 +98,9 @@ REopt.add_flexible_hvac_results
 ## SteamTurbine outputs
 ```@docs
 REopt.add_steam_turbine_results
-```
+```
+
+## CST outputs
+```@docs
+REopt.add_concentrating_solar_results
+```