Edit: Select All
edit.selectAll Select the whole document.
How to run it
Open the command palette (M-x in the Emacs keymap) and search for Edit: Select All, then press Enter. It also has a default keybinding:
| Emacs | C-xh |
| CUA | C-a |
| Sublime Text | C-a |
| VS Code | C-a |
| IntelliJ IDEA | C-a |