Command 'O' does not indent automatically with an incomplete line

[MrHate]

Describe the bug
As the title goes.

To Reproduce

1. Code an incomplete line in a C++ source file(and it is indented);
2. Press 'O';
3. See error.

Expected behavior
Create a new line with the same indentation.

Screenshots

Environment

• Extension (VsCodeVim) version: 1.13.1
• VSCode version: 1.44.2
• OS: macOS Catalina 10.15.4

[J-Fields]

This is ultimately caused by the same issue as #1017 (comment). O basically just calls editor.action.insertLineBefore, and the resulting indentation is determined by the language extension.