How can I make it so that no command or extra keystroke is required for the autocompletion menu to pop up?
i.e. what I want is the menu to be always present while in insert mode and to be constantly updating its suggestions as I type.
If you're looking for a super simple solution, you can add the code from this page to your .vimrc. https://gist.github.com/maxboisvert/a63e96a67d0a83d71e9f49af73e71d93
There is also a plugin version of it which can be found here. https://github.com/maxboisvert/vim-simple-complete
I'm personally using https://github.com/maralla/completor.vim for this, it's very lightweight and requires no configuration to work. It doesn't do any fancy stuff or alter what's shown in the completion pop-up in any way, it will simply auto show the completion pop-up whenever it can.
I'm also using these settings for it, to make it more ergonomical:
" Select autocomplete item with Tab
inoremap <expr> <Tab> pumvisible() ? "\<C-Y>" : "\<Tab>"
" Don't autoselect an item from the completion menu, and always show the menu
let g:completor_complete_options='menuone,noinsert'
" No delay on showing the completion pop-up
let g:completor_completion_delay=0
set completeopt?to see if this option is correctly set. Some other plugins or settings may override this option – jdhao Aug 8 '19 at 1:57