Pressing Enter inserts two line breaks in contenteditable

Phenomenon

In Chrome on macOS, pressing Enter in a contenteditable region inserts two line breaks (<br> elements) instead of one, causing unexpected spacing between paragraphs.

Reproduction example

1. Create a contenteditable div.
2. Type some text.
3. Press Enter to create a new line.
4. Observe the DOM structure.

Observed behavior

• In Chrome on macOS, pressing Enter creates two <br> elements.
• This results in double spacing between lines.
• The behavior is inconsistent with other browsers.

Expected behavior

• Pressing Enter should insert a single line break or create a new paragraph element.
• The spacing should be consistent with standard text editing behavior.