Issue with host autocomplete when hosts contain ‘@‘ symbol

Being anal retentive, I’ve chosen to setup my hosts in the following format:

```
@.:
```

If I have two hosts configured, say:

```
william@example1.com:22
william@example2.com:22
```

Attempting to autocomplete either host goes something like this:

1. 
2. ` key`
3. 
4. `<1> key`
5. 
6. ` key`
7. 

Obviously, I can work around this by renaming my hosts, but just thought I should let you know. Thanks!

No source file or test is identified in the issue. Reproduce host autocomplete with william@example1.com:22 and william@example2.com:22, then locate the autocomplete entry point and trace how the @ symbol is handled; done means both hosts can be selected without the demonstrated extra key sequence.

Written by the indexing model from the issue text.