enable automatically-generated "pseudolocale"

[cfm]

Description

A Weblate "pseudolocale" would help us (manually) spot strings not correctly marked for translation during QA.

See also: freedomofpress/securedrop#6690

How will this impact SecureDrop users?

No direct impact to users.

How would this affect the SecureDrop Workstation threat model?

No changes to the current internationalization flow and its security model.

User Stories

As a QA tester, I want to be able to tell at a glance whether a string in the Client has not yet been translated or is incorrectly not marked for translation.

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Testing

In freedomofpress/securedrop-client-i18n-sandbox from weblate-sandbox.securedrop.org:

1. Pseudolocale defined: https://weblate-sandbox.securedrop.org/projects/securedrop/securedrop-client/en_XA/
2. Pseudolocale generation configured
3. export LANG=en_XA; ./run.sh works as expected

Production

In freedomofpress/securedrop-client from weblate.securedrop.org:

• Replicate above configuration: https://weblate.securedrop.org/projects/securedrop/securedrop-client/en_XA/
• Document use in QA: docs: add reminder for pseudolocale QA #1620

[cfm]

Following freedomofpress/securedrop#6690, this is done pending the documentation proposed in #1620. Happily, because we don't use Babel here, we're able to use Weblate's suggested (although not CLDR-valid) en_XA pseudolocale.