wgrep editing is newly broken (last working ~3wks ago)

### I confirm that...

- [x] I have searched the [issue tracker](https://github.com/doomemacs/doomemacs/issues), [documentation](https://docs.doomemacs.org), [FAQ](https://docs.doomemacs.org/-/faq), [Discourse](https://discourse.doomemacs.org), and [Google](https://google.com), in case this issue has already been reported/resolved.

- [x] I have read "[How to Debug Issues](https://doomemacs.org/d/how2debug)", and will use it to provide as much information about this issue as possible.

- [x] The issue can be reproduced on the **latest** available commit of Doom.

- [x] The issue can be reproduced on a stable release of Emacs, such as 27, 28, or 29. *(Unstable versions end in .50, .60, or .9x)*

### Steps to reproduce

Start with these two text files:

Search in the project / all buffers / etc:

Edit wgrep result:

Then execute `wgrep-finish-edit`.

The entire wgrep edit buffer is now appended after the 1st edited line:

### System Information

https://pastebin.com/Nyzi07kc

Reproduce the failure with the two text files and the search/edit steps in the issue, then start at the wgrep-finish-edit entry point. Done means finishing the wgrep edit updates each edited file in place instead of appending the entire edit buffer after the first edited line.

Written by the indexing model from the issue text.