Single leading spaces before other text are not visible in Firefox

In Firefox, a single space typed at the beginning of existing text is not displayed. Typing a second space will make two spaces appear. I can reproduce this in my own app as well as in the Trix editor on Basecamp.

##### Steps to Reproduce

1. Load a page with an empty Trix editor in Firefox
2. Enter the text 'foo' in the editor
3. Go to the beginning of the text and type a single space
4. The space does not appear

##### Details

* Trix version: 1.3.1
* Browser name and version: Firefox 99.0
* Operating system: Linux

Start by reproducing the issue in the Trix editor on Firefox 99 using the listed steps, then compare the behavior with other browsers. The work is done when a single leading space typed before existing text is visibly preserved without requiring a second space.

Written by the indexing model from the issue text.