VS Code extension: Enter used to commit an IME conversion submits the inline comment on a plan

Description

In the VS Code extension, when writing an inline comment on a selected part of a plan, pressing Enter to commit an IME conversion (Japanese input) is treated as "submit the comment" instead of "confirm the conversion".

As a result, unconverted or half-written text gets submitted, which makes it practically impossible to finish writing a comment in Japanese.

Steps to reproduce

1. Open a plan in the VS Code extension
2. Select any part of the plan to open the inline comment input
3. Switch to Japanese input (IME) and type some text
4. Press Enter to commit the IME conversion
5. The comment is submitted instead of the conversion being committed

Expected behavior

• Submitting an inline comment should be bound to Cmd + Enter
• Enter alone should commit the IME conversion and insert a newline
• Enter pressed while an IME composition is active should never submit

This is not limited to Japanese — the same problem should occur for any language that uses an IME, such as Chinese and Korean.