Update keyboard demo text (#4540)
Update keyboard demo text (#4540)


rachel-fenichel/blockly,rachel-fenichel/blockly,rachel-fenichel/blockly,rachel-fenichel/blockly,google/blockly,google/blockly,mark-friedman/blockly,rachel-fenichel/blockly,mark-friedman/blockly,google/blockly,google/blockly,google/blockly,mark-friedman/blockly,mark-friedman/blockly,rachel-fenichel/blockly,google/blockly,rachel-fenichel/blockly,google/blockly,mark-friedman/blockly,mark-friedman/blockly