Add keyboard input RShift, tilde, "no key up" tokens and debug buttons

These are used to add support for vrc debug commands which I personally wanted to add. Because it's a narrow use case the must be enabled manually by adding vrcDebug = true to [utilitiesSettings] in the OpenVRAdvancedSettings.ini file

src/keyboard_input/input_parser.cpp

@@ -308,7 +308,11 @@ bool isModifier( const Token token ) noexcept
         [[fallthrough]];
     case Token::MODIFIER_SHIFT:
         [[fallthrough]];
+    case Token::MODIFIER_RSHIFT:
+        [[fallthrough]];
     case Token::MODIFIER_SUPER:
+        [[fallthrough]];
+    case Token::MODIFIER_TILDE:
         return true;
     default:
         return false;