Enhance error when locale fails to setup

[benoit74]

Fix #157

• Enhance locale setup error message for easier understanding
• Add more information about locale requirement in README

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 99.93%. Comparing base (efc2942) to head (5d3ee5a).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #180 +/- ## ======================================= Coverage 99.93% 99.93% ======================================= Files 33 33 Lines 1546 1549 +3 Branches 279 279 ======================================= + Hits 1545 1548 +3 Partials 1 1 ```

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