[WIP] Update update_analyzer docs to specify updatable properties

[Copilot]

Thanks for assigning this issue to me. I'm starting to work on it and will keep this PR's description up to date as I form a plan and make progress.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[azure-ai-contentunderstanding] update_analyzer docs should clarify which properties are updatable</issue_title>
<issue_description>## Description

The update_analyzer method in ContentUnderstandingClient currently has documentation that says only "Update analyzer properties" without specifying which properties can actually be updated.

The underlying REST API uses PATCH with application/merge-patch+json, and only description and tags are accepted by the service. All other properties (models, field_schema, config, base_analyzer_id, dynamic_field_schema, processing_location, knowledge_sources) are create-only — they are silently ignored by the server even though it returns HTTP 200.

Requested Improvements

1. API doc (docstring): Add documentation to update_analyzer listing the updatable properties and noting that other properties require begin_create_analyzer with allow_replace=True.

2. Samples: If an update analyzer sample exists, add a note explaining that only description and tags are updatable via this method, and reference begin_create_analyzer with allow_replace=True for changing models, field_schema, etc.

Updatable Properties

Property	Updatable via update_analyzer (PATCH)?
description	Yes
tags	Yes
models	No — silently ignored
field_schema	No — silently ignored
config	No — silently ignored
base_analyzer_id	No — silently ignored
dynamic_field_schema	No — silently ignored
processing_location	No — silently ignored
knowledge_sources	No — silently ignored

Workaround

To change create-only properties on an existing analyzer, use begin_create_analyzer with allow_replace=True. This calls PUT (full resource replacement) instead of PATCH.

Related

• [BUG][Azure.AI.ContentUnderstanding] Update of analyzer is not working properly azure-sdk-for-net#57215 — customer report of UpdateAnalyzerAsync not updating models
• [Azure.AI.ContentUnderstanding] UpdateAnalyzer/UpdateAnalyzerAsync docs should clarify which properties are updatable azure-sdk-for-net#57231 — .NET documentation issue
• [azure-ai-contentunderstanding] updateAnalyzer docs should clarify which properties are updatable azure-sdk-for-java#48469 — Java documentation issue
• [@azure/ai-content-understanding] updateAnalyzer docs should clarify which properties are updatable azure-sdk-for-js#37728 — JavaScript documentation issue
  </issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [azure-ai-contentunderstanding] update_analyzer docs should clarify which properties are updatable #45789

---

💬 Send tasks to Copilot coding agent from Slack and Teams to turn conversations into code. Copilot posts an update in your thread when it's finished.