Fix typos in the project overview text files.

Bootloaders/CDC/BootloaderCDC.txt

Bootloaders/DFU/BootloaderDFU.txt

Demos/Device/ClassDriver/GenericHID/GenericHID.txt

Demos/Device/ClassDriver/Joystick/Joystick.txt

Demos/Device/ClassDriver/Keyboard/Keyboard.txt

Demos/Device/ClassDriver/KeyboardMouse/KeyboardMouse.txt

Demos/Device/ClassDriver/MIDI/MIDI.txt

Demos/Device/ClassDriver/MassStorage/MassStorage.txt

...e/ClassDriver/MassStorageKeyboard/MassStorageKeyboard.txt

Demos/Device/ClassDriver/Mouse/Mouse.txt

Demos/Device/ClassDriver/VirtualSerial/VirtualSerial.txt

...ice/ClassDriver/VirtualSerialMouse/VirtualSerialMouse.txt

Demos/Device/LowLevel/GenericHID/GenericHID.txt

Demos/Device/LowLevel/Joystick/Joystick.txt

Demos/Device/LowLevel/Keyboard/Keyboard.txt

Demos/Device/LowLevel/KeyboardMouse/KeyboardMouse.txt

Demos/Device/LowLevel/MIDI/MIDI.txt

Demos/Device/LowLevel/MassStorage/MassStorage.txt

Demos/Device/LowLevel/Mouse/Mouse.txt

Demos/Device/LowLevel/VirtualSerial/VirtualSerial.txt