added credits name and explanation for the options menu

stepmania/Themes/default/Languages/en.ini

@@ -367,6 +367,7 @@ Sound Options=Change volume and resampling options.
 SoundResampleQuality=Advanced: Select the resampling quality to use.
 SoundVolume=SoundVolume
 Speed=Speed
+Stepmania Credits=The Stepmania Development Team
 Steps=Steps
 Style=
 Test Input=Test the responsiveness of connected joysticks.
@@ -821,6 +822,7 @@ ShowSelectGroup=Song\nGroup
 ShowSongOptions=Show Song\nOptions
 ShowStats=Show\nStats
 SmoothLines=SmoothLines
+Stepmania Credits=Stepmania Credits
 Center1Player=Center\n1 Player
 Song=Song
 Song Group=Song Group
@@ -1353,6 +1355,7 @@ HelpText=Use &UP; &DOWN; to select, then press START
 Jukebox=Jukebox
 Select Game=Select Game
 Theme=Theme
+Credits=Credits
 
 [ScreenWithMenuElementsBlank]
 HelpText=