cp: preserved hardlinks are not reported in --verbose

[Ben Wiederhake]

This probably affects other types/modes of copying, too, since we have a lot of shurt-cutting currently.

Steps to reproduce:

• Have two files that are hardlinks
• Copy them with -dv to some other directory

Expected behavior: Both files are copied, the resulting two files are hardlinks of each other but not of the original files, and both copy operations are reported.

Actual behavior: Both files are copied, the resulting two files are hardlinks of each other but not of the original files, but only one copy operation is reported.

Demonstrator:

$ ln README.md README.md.hd
$ rm -f target/README.md* && ../gnu/src/cp -dv README.md README.md.hd target/ && ls -i README.md README.md.hd target/README.md target/README.md.hd
'README.md' -> 'target/README.md'
'README.md.hd' -> 'target/README.md.hd'
20093851 README.md  20093851 README.md.hd  20928436 target/README.md  20928436 target/README.md.hd
$ rm -f target/README.md* && cargo run cp -dv README.md README.md.hd target/ && ls -i README.md README.md.hd target/README.md target/README.md.hd
'README.md' -> 'target/README.md'
20093851 README.md  20093851 README.md.hd  20928436 target/README.md  20928436 target/README.md.hd
$

(In this example, the copied files "randomly" got the same inode ID twice in a row, but they might have gotten a different ID in the second run.)

Found while reviewing #6208