Some printable characters appear urlencoded or double-urlencoded

**Describe the bug:**

## 1

When I click on the Authenticator icon on the Google Chrome toolbar, and look at various entries, some of them show some printable characters in urlencoded form.

`@` becomes %40
space becomes %20
`+` becomes %2B

An email address like `user@example.com` might appear as `user%40example.com`.

This type of urlencoding seems to be happening in both the upper and lower lines that identify each entry.

The reason I think this is a bug is because, even when urlencoding is needed, the urlencoded string would normally be urldecoded before it is displayed to the user.

The above has been happening for quite some time, at least since a year ago. Surprisingly, I don't find any existing issue that mentions this.

More surprisingly, sometimes urlencoding appears to have been done twice in the lower line.

`@` becomes %2540
space becomes %2520

An email address like `user@example.com` might appear as `user%2540example.com`. Here, the % in %40 was urlencoded into %25.

If I edit any of these urlencoded or double-urlencoded these entries, they then appear normal. So I can edit `user%40example.com` to correct it to `user@example.com` and it will then appear as `user@example.com`.

Note: A previous issue #63 mentions non-standard characters but I can't tell if it has any relevance here.

## 2

A second related issue is that it's not possible to use the / operator to search for a string like %40 and then edit all the matching entries to correct them to show @ instead. The reason being that as soon as one begins editing %40, the match fails and that particular entry disappears from view. Please see a previously reported issue #289.

## 3

**Platform:** Ubuntu Linux 16.04.6 LTS (Xenial Xerus)
- Browser: Google Chrome
- Browser Version: 79.0.3945.88 (Official Build) (64-bit)

El informe no identifica ningún archivo fuente ni ninguna prueba. Reproduce el problema mostrando y editando entradas que contengan @, espacios y + en la Chrome extension; después, inspecciona el comportamiento de visualización, edición y búsqueda; se considera terminado cuando las entradas muestran texto decodificado y buscar o editar valores codificados no hace que desaparezcan.

Escrito por el modelo de indexación a partir del texto del issue.