Accidental multi-line paste breaks file picker

[o-sdn-o]

Repro:

• Press Ctrl+O to open file picker
• Paste any multi-line fragment with enough lines, e.g. >100
• Press Esc to close the file picker
• Press Ctrl+O again and check that the file picker is not usable

If the multi-line fragment contains slashes, then pressing Enter will change the current directory to a random string.

[o-sdn-o]

In addition, if you save a file with such a multi-line name (tested on wsl), a file with a name containing \n characters will be created. Then this file cannot be opened.