Remove trailing " [" from common substring when loading BMS files.

src/NotesLoaderBMS.cpp

@@ -1104,6 +1104,18 @@ bool BMSLoader::LoadFromDir( const RString &sDir, Song &out )
 	map<RString,int> idToKeysoundIndex;
 	ReadGlobalTags( aBMSData[iMainDataIndex], out, sigAdjustments, idToKeysoundIndex );
 
+	// The brackets before the difficulty are in common substring, so remove them if it's found.
+	if( commonSubstring.size() > 2 && commonSubstring[commonSubstring.size() - 2] == ' ' )
+	{
+		switch( commonSubstring[commonSubstring.size() - 1] )
+		{
+		case '[':
+		case '(':
+		case '<':
+			commonSubstring = commonSubstring.substr(0, commonSubstring.size() - 2);
+		}
+	}
+	
 	// Override what that global tag said about the title if we have a good substring.
 	// Prevents clobbering and catches "MySong (7keys)" / "MySong (Another) (7keys)"
 	// Also catches "MySong (7keys)" / "MySong (14keys)"