test: Add tests for function `<mother_core::scanner::language::Language>::extensions`

**File:** `crates/mother-core/src/scanner/language.rs:0`

**Function:** `<mother_core::scanner::language::Language>::extensions`

**Coverage:** 0.0%

**Severity:** warning

## Description

This function has insufficient test coverage. Please add tests to cover:

- Normal/happy path
- Edge cases
- Error conditions
- Boundary values

---
*Auto-generated by coverage*