Add automotive provider for en_IN locale

[ShriyansBharuka]

What does this change

Adds the automotive provider for the en_IN (English - India) locale, providing realistic and compliant vehicle registration plate generation for India.

What was wrong

The en_IN locale lacked an automotive provider. Calling Faker('en_IN').license_plate() fell back to the default US format (e.g. 912 AFE), which is completely inaccurate for Indian datasets.

How this fixes it

Implements faker.providers.automotive.en_IN.Provider according to the standards established by the Ministry of Road Transport and Highways (MoRTH):

1. Standard Vehicle Registration Plates (Central Motor Vehicles Rules, 1989 Rules 50 & 51):
   • Supports all 28 States and 8 Union Territories with official two-letter codes (MH, DL, KA, TN, UP, GJ, WB, etc.).
   • Accurate 2-digit RTO district codes (01–99).
   • Standard 1-2 letter series codes and 4-digit unique numbers (0001–9999).
   • Example: MH 12 AB 1234, DL 01 C 4521, KA 05 MN 9876.
2. Bharat Series (BH Series) (Central Motor Vehicles Twentieth Amendment Rules, 2021):
   • Format: YY BH #### XX (with letters I and O excluded as per MoRTH regulations).
   • Example: 22 BH 1234 AA.
3. Dedicated methods:
   • license_plate()
   • standard_license_plate()
   • bharat_series_license_plate()
4. Added comprehensive test coverage in tests/providers/test_automotive.py (TestEnIn). All 115 automotive test cases pass.

AI Assistance Disclosure (REQUIRED)

• If AI tools were used, I have disclosed which ones, and fully reviewed and verified their output.

Disclosure: Gemini was used to assist in researching MoRTH/CMVR regulatory specifications and generating initial test regex patterns. All state codes, logic, and test suites were manually reviewed and verified locally with pytest.

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Checklist

• I have read the documentation about CONTRIBUTING
• I have read the documentation about Coding style
• I have run make lint