tab 自动换行（tab - automatic line break）

一行字符超过一定字数后，行尾的 tab 就会另启一行。但这行的末尾还有很多空间。

When a line of characters exceeds a certain length, the tab at the end of the line will start a new line. However, there is still plenty of space at the end of this line.

Reproduce the tab-wrapping behavior in MacDown with a long line that still has visible space at the end, using the screenshot and bilingual description as the expected case. Trace the editor's line-wrapping behavior; done means a trailing tab stays on the current line when sufficient space remains.

Written by the indexing model from the issue text.