Convert for Notepad++ v4.6 release

1. Add accurate description for all API (messages for sending to Notepad++).
2. Update header files.

923dd89d1f7f7693b37a7019e6ef9e58ea14dec0b768e62d3860545734c01c11  NppConvert.v4.6.arm64.zip
f80d8266112bb50e4aff95c8d1ddfb9dbc2562e380d33820dd5f85368747a2cc  NppConvert.v4.6.x64.zip
61826fee7b91ded1db1de7d16cf16b71172510c8abe5486ade06664cc1af06c9  NppConvert.v4.6.zip