fix(specs): ingestion small fix + added source input descriptions

[sbellone]

Remove platform from the "Update Source" documentation

When trying to update the platform attribute of an authentication, I got the following error:

{
  "error": {
    "code": "invalid_payload"
  },
  "message": "unknown field \"platform\"",
  "status": 400
}

From what I see in the code, this is expected so this PR removes this attribute from the documentation.

Add a description of the various sources inputs

Currently the inputs are missing a description, and our new docs platform render them as "Option xx", so we have to guess which option corresponds to which source type:

[algolia-bot]

💥 Breaking changes detected !!

Either this PR or a previous PR not released yet introduced breaking changes, be careful when merging.
You can find the details in the 'client java@21' CI job.

✔️ Code generated!

Name	Link
🪓 Triggered by	91a9cd9e389a225f9967b171f85dd2e303bd1a73
🍃 Generated commit	7a67669a94ed69a405c117d6c0dcb110964a615d
🌲 Generated branch	generated/fix/specs-ingestion-small-fixes

📊 Benchmark results

Benchmarks performed on the method using a mock server, the results might not reflect the real-world performance.

Language	Req/s
go	1930
javascript	1640
php	1469
csharp	1265
python	1119
java	1003
ruby	793
swift	737
scala	23

[shortcuts]

thank you boss