Use heading markdown to demarcate sections of commands

Its a little tought to notice that the COMMANDS section is actually 3 sections. Use markdown to make this easier to see for the user.

sway/sway.5.scd

@@ -52,7 +52,7 @@ Throughout the documentation, *|* is used to distinguish between arguments for
 which you may only select one. *[...]* is used for optional arguments, and
 *<...>* for arguments where you are expected to supply some value.
 
-# COMMANDS
+# COMMANDS - CONFIG ONLY
 
 This section only lists general commands. For input and output commands, refer
 to *sway-input*(5) and *sway-output*(5).
@@ -98,6 +98,8 @@ The following commands may only be used in the configuration file.
 	machines, it may be desirable to have Xwayland started immediately by
 	using _force_ instead of _enable_.
 
+# COMMANDS - RUNTIME ONLY
+
 The following commands cannot be used directly in the configuration file.
 They are expected to be used with *bindsym* or at runtime through *swaymsg*(1).
 
@@ -385,6 +387,8 @@ set|plus|minus|toggle <amount>
 
 	The default format is "%title".
 
+# COMMANDS - CONFIG OR RUNTIME
+
 The following commands may be used either in the configuration file or at
 runtime.