Duplication without formatting

[NathanStanislavsky]

Describe the bug

When Sanity AI is told to make changes to the body field it duplicates the entire body and adds it to the bottom of the body field without formatting.

To Reproduce

Steps to reproduce the behavior:

1. Paste the following content into the body field of a Sanity page and format as shown in the image below.

Title H2

This sentence should be bold

This sentence should be italics

This sentence should be underlined

This word should be bold

This word should be italic

This word should be underlined

This sentence should be code

This word should be code

This sentence should be strikethrough

This word should be struck through

Title H3

This sentence should be bold

This sentence should be italics

This sentence should be underlined

This word should be bold

This word should be italic

This word should be underlined

This sentence should be code

This word should be code

This sentence should be strikethrough

This word should be struck through

2. Open Sanity AI and give it the following instruction:

   
   Remove any sentences that do not end in periods from the [Field]

Remove any sentences from the [Field] that do not have a complete thought.

Make sure to add the correct field in [Field] using the "insert field" feature.

**Expected behavior**

I expect the AI to remove all sentences that do not end in periods and aren't complete thoughts. This should be the final result:

<img width="606" alt="Screenshot 2024-08-05 at 4 07 12 PM" src="https://github.com/user-attachments/assets/75e52a73-16ca-4221-8b9f-e6badf437361">

**Which versions of Sanity are you using?**

@sanity/cli (global)  3.52.0 (latest: 3.52.4)

**What operating system are you using?**

macOS Sonomi 14.4

**Which versions of Node.js / npm are you running?**

node -v
v20.14.0

npm -v
10.7.0