[mateen993]

What

Fixes two README examples that describe IPGeolocation.io as rate-limited.

Response Metadata example

• Removed firstHeaderValue("x-ratelimit-remaining"). The API never sends this header, so the line prints undefined.
• Now shows metadata.creditsCharged and the raw x-credits-charged header, which the API returns on every billed call.

Error Handling example

• RateLimitError (429) now logs "Out of API credits" with error.apiMessage instead of "Rate limit reached".
• Added a comment: 429 means credits are used up for the period (or the overage limit is reached), not a per-second limit.
• Kept the class name RateLimitError so existing code keeps working.

Checked

One /v3/ipgeo lookup with SDK 3.0.1 on Node 22 returns:

statusCode: 200
creditsCharged: 1
firstHeaderValue("x-ratelimit-remaining"): undefined
firstHeaderValue("x-credits-charged"): 1

The SDK source agrees: creditsCharged is parsed from X-Credits-Charged, and a 429 response maps to RateLimitError.

Follow-up

Publish this README in the next npm release so the package README matches.