GeezerVison

Fixes uutils#223. Very simple reproduction

```
cd diffutils
mkdir a
touch a/alef  a/alefn  a/alef_  a/alefx  a/alefr  a/fuzz.file
cargo test
```
 => fail

https://www.gnu.org/software/diffutils/manual/html_node/Multiple-Patches.html
states that the "old" file name has precedence over the "new" filename.

I hit this problem because some other (and unfortunately: unknown for
now) test issue left bogus `a/alef*` file(s) behind in my workspace. I
didn't bother cleaning them up because I assumed some test would keep
recreating them and that cost me a lot of time.

This issue seems to have existed since the very first commit.
Interestingly, there as a previous attempt in 2024 to fix this in commit
a3a372f ! So I was apparently not the only affected. BUT that
fix was immediately reverted by commit ba7cb0a in the same
PR. Admittedly, that fix seemed somewhat off-topic in
uutils#33. So here it is again.