Add missing documentation for disable battleground respawn

[AnnieRuru]

Pull Request Prelude

• I have followed proper Hercules code styling.
• I have read and understood the contribution guidelines before making this PR.
• I am aware that this PR will be closed if the above-mentioned criteria are not fulfilled.

Issues addressed

Add missing documentation for disable battleground respawn

Tested with

... erm ...
https://github.com/AnnieRuru/customs/blob/master/scripts/bg_pvp_point_queue.txt
just change

	.red = bg_create_team( "guild_vs3", 13,50 );
	.blue = bg_create_team( "guild_vs3", 86,50 );

into

	.red = bg_create_team( "-", 13,50 );
	.blue = bg_create_team( "-", 86,50 );

Affected Branches

• Master

Known Issues and TODO List

well, pressing the [Return to last Save Point] from the client side will forcefully leave the battleground team though

[HerculesWSAPI]

This change is