Attempt to import encrypted key fails with `nom` parser error

[link2xt]

I generated a passphrase-protected key:

$ sq key generate --userid [email protected] --output key.asc --with-password 
Enter password to protect the key: 
Repeat the password once more:

(entered 123 as a password twice)

Then tried to import the key:

$ RUST_LOG=deltachat_repl=info cargo run -p deltachat-repl -- deltachat-db
...
Delta Chat Core is awaiting your commands.
 INFO  deltachat_repl > src/sql.rs:292: Opened database "deltachat-db".
> import-keys key.asc
 INFO  deltachat_repl > src/imex.rs:378: Import/export dir: key.asc
 INFO  deltachat_repl > Received IMEX_PROGRESS(10 ‰)
 INFO  deltachat_repl > src/imex.rs:616: Importing secret key from key.asc as the default key.
Error: incomplete input: Size(5220)
 ERROR deltachat_repl > IMEX failed to complete: incomplete input: Size(5220)
 INFO  deltachat_repl > Received IMEX_PROGRESS(0 ‰)

This actually should be fixed in rPGP, but I have not tried to make a testcase for rPGP yet.

"incomplete input" is an internal parser error rather than a proper error that tells users what the problem is. Originally reported at https://support.delta.chat/t/cannot-import-private-key-from-text-file/2846