It's probably one of two things:
The cmdheight setting is 2 or higher; you can check the current value with :set cmdheight?, and set it to the default of 1 with :set cmdheight=1. There's something in your vimrc or a plugin changing from the default, you can use :verbose set cmdheight? to see where it was last set.
The terminal screen isn't quite big enough ...
One way to get this feature is by using coc and coc-emoji.
Coc is a plugin which allows you to get the same Language Server Protocol (autocompletion, linting, go to definition, etc...) as VSCode because it uses the same extensions as VSCode. This is a pretty powerful tool but installing it just to get emoji support might be a bit overkill.
However if you do ...
The automatic bookmarks '< and '> get updated only after the Visual mode is left. Hence <Cmd> is not useful for your example, as you effectively apply the previous selection range, not the current one.
You really should use "normal colon"-mapping here:
xnoremap <Leader>c :w !xsel<CR>
Note (1) use xnoremap instead of ...
I don't think you need exec in your command. !open <URL> in itself is a complete command recognized by Vim. So simply,
:silent !open https://vi.stackexchange.com/
EDIT: As OP mentioned edits so here is a detailed explanation of why URLs containing ampersand & won't work without using either quotes or escape character.
In OP's edit 2 ...
It should be no different from Vim. Namely,
In nvim help :h vimrc describes how the associated file is (still) referred to as a "vimrc" (or "config file") and just below that (:h $MYVIMRC) you'll see how/when the environment variable $MYVIMRC is assigned, i.e. during startup nvim looks for config in four places (vs five ...
You could search /MARK and then hit n, but faster and easier in my opinion is
And then you type : and the line number when you get the list of results.
The command can be shortened to :g/MARK/#, if you like, or mapped to a keysequence to make it even faster:
nnoremap <leader>m :global/MARK/#<CR>:
Setting LANG to tr_TR.UTF-8 did solve the issue.
Turns out LANG being empty was the root cause:
I only checked through ...
The solution I found to this problem is to comment out the lines in the Windows Terminal settings.json binding copy and paste to Ctrl+C and Ctrl+V respectively. By default, they are bound to Ctrl+Shift+C and Ctrl+Shift+V.
// Copy and paste are bound to Ctrl+Shift+C and Ctrl+Shift+V in your defaults.json.