obs-nvenc: Add missing locale text

[shiina424]

Description

The translation string does not exist in en-US.ini. In version 30.2.3, this string has been translated.

Motivation and Context

I want to display translations.

How Has This Been Tested?

I tested by changing the local translation file. (ja-JP.ini)

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• [ ] My code has been run through clang-format.
• [x] I have read the contributing document.
• [x] My code is not on the master branch.
• [x] The code has been tested.
• [x] All commit messages are properly formatted and commits squashed where appropriate.
• [x] I have included updates to all appropriate documentation.