Command Mode

**Is your feature request related to a problem? Please describe.**
As transcription is not always as expected, from time to time it's necessary to rephrase, check Grammer and Spelling or Reformat the text.

**Describe the solution you'd like**
To activate Command Mode, press Fn + Cmd on Mac, Ctrl + Win +Alt on Windows
If you had highlighted text: Say a command and HEX will directly edit the text. You can ask practically anything but being descriptive is necessary. The updated text will replace the text you’ve highlighted.

**Describe alternatives you've considered**
Create several shortcuts and give the user possibility to Enter short prompts for each button, which is then processed to the highlighted text, for example option+1 = Check grammar and spelling; option+2 = Translate ENG<>GER.

The issue names no files or tests. Start by locating the macOS shortcut handling and the flow for editing highlighted text; done means Command Mode can be activated on each platform, accepts a spoken command, and replaces selected text with the updated result.

Written by the indexing model from the issue text.