config: add time, vsync explanation

bin/MangoHud.conf

@@ -8,7 +8,7 @@
 ### Limit the application FPS
 # fps_limit=
 
-### VSYNC [0-3]
+### VSYNC [0-3] 0 = adaptive; 1 = off; 2 = mailbox; 3 = on
 # vsync=
 
 ################### VISUAL ###################
@@ -24,6 +24,9 @@ gpu_stats
 ### Display the frametime line graph
 frame_timing
 
+### Display the current system time
+# time
+
 ### Change the hud font size (default is 24)
 font_size=24
 
@@ -33,10 +36,8 @@ position=top-left
 ### Display the current CPU load & frequency for each core
 # core_load
 
-### Display system memory usage
+### Display system ram / vram usage
 # ram
-
-### Display system video memory usage
 # vram
 
 ### Disable / hide the hud by deafult