ls: honor LC_NUMERIC for the -h decimal separator

ls -lh (and -h) rendered the fractional size with a period regardless of
LC_NUMERIC, so under e.g. fr_FR.UTF-8 it printed "8.4K" where GNU prints
"8,4K". ls already formats sizes through uucore's human_readable, which
localizes the separator, but the ls crate did not enable the
`i18n-decimal` uucore feature, so the localization compiled out.

Enable it, matching what du does (see #12357). This makes ls -h agree
with sort -h under a comma-decimal locale.

Fixes #14232

Author: Jorge-Polanco-Roque

src/uu/ls/Cargo.toml

@@ -33,6 +33,7 @@ uucore = { workspace = true, features = [
   "fsext",
   "fsxattr",
   "i18n-collator",
+  "i18n-decimal",
   "parser-size",
   "parser-glob",
   "quoting-style",

tests/by-util/test_ls.rs

@@ -7734,6 +7734,27 @@ fn test_write_error() {
         .stderr_is("ls: write error: No space left on device\n");
 }
 
+#[test]
+#[cfg_attr(wasi_runner, ignore = "WASI: locale env vars not propagated")]
+fn test_ls_h_locale_decimal_separator() {
+    // `ls -lh` must render the fractional size with the LC_NUMERIC decimal
+    // separator, like GNU (and like `du -h`), so `ls -lh | sort -h` agrees.
+    for (locale, expected) in [("fr_FR.UTF-8", "8,4K"), ("C", "8.4K")] {
+        let (at, mut ucmd) = at_and_ucmd!();
+
+        let fpath = at.plus("test.txt");
+        std::fs::File::create(&fpath)
+            .expect("cannot create test file")
+            .set_len(8500)
+            .expect("cannot truncate test len to size");
+        ucmd.env("LC_ALL", locale)
+            .arg("-lh")
+            .arg(&fpath)
+            .succeeds()
+            .stdout_contains(expected);
+    }
+}
+
 #[cfg(all(feature = "feat_diagnostics", not(wasi_runner)))]
 mod diagnostics {
     use super::*;