(DOCSP-35191): C++: Add details around REALM_SCHEMA and namespace realm

[dacharyc]

Pull Request Info

Jira ticket: https://jira.mongodb.org/browse/DOCSP-35191

• Define an Object Model: Minor updates throughout the page for consistency, including naming updates. The main change as requested in the Jira ticket is in the "Define a New Object Type" section.
• CRUD/Create: Explicitly mention that when you define a new object, you must do it using the realm namespace.

Reminder Checklist

Before merging your PR, make sure to check a few things.

• Did you tag pages appropriately?
  • genre
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• Describe your PR's changes in the Release Notes section
• Create a Jira ticket for related docs-app-services work, if any

Release Notes

• *C++ SDK
  • Model Data/Define an Object Model: Add information and update code examples to show defining a model in the realm namespace.
  • CRUD/Create: Explicitly mention that when you define a new object, you must do it using the realm namespace.

Review Guidelines

REVIEWING.md

[github-actions]

Readability for Commit Hash: 7839116

You can see any previous Readability scores (if they exist) by looking
at the comment's history.

Readability scores for changed documents:

• source/sdk/cpp/model-data/object-models: Grade Level: 9.4, Reading Ease: 55.64
• source/sdk/cpp/crud/create: Grade Level: 9.5, Reading Ease: 50.02

For Grade Level, aim for 8 or below.

For Reading Ease scores, aim for 60 or above:

Score	Difficulty
90-100	Very Easy
80-89	Easy
70-79	Fairly Easy
60-69	Medium
50-59	Fairly Hard
30-49	Hard
0-29	Very Hard

For help improving readability, try Hemingway App.

[cbullinger]

lgtm! simplifying to "database" and "object" is going to help with clarity, I think

[cbullinger]

...if all sync databases are necessarily Atlas databases, is that a possible term we can use (the "device database" vs. the "Atlas database")?

[dacharyc]

I don't think I'm following this Q. Let's talk about this when we sync on naming updates so we're making consistent updates across the SDKs.

[docs-builder-bot]

✨ Staging URL: https://docs-mongodborg-staging.corp.mongodb.com/realm/docsworker-xlarge/master/

🪵 Logs

• job log: 440b0ee7feb4c3925874fb7490d6b2da6259452a