Satisfy clippy 1.95's clippy::unnecessary_trailing_comma lint

Clippy 1.95 introduced a new default warning that flags trailing
commas after the last argument of format-like macros. Four sites
across the license tests were written with a trailing comma before
the closing parenthesis — all in `assert!` and `format!` calls where
there is no argument following the comma. Drop those four commas;
no behaviour change.

The lint was not present in the clippy 1.94 CI runner, which is why
the earlier pushes didn't surface it. Surfaced now because rustup
updated the toolchain locally.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: EliahKagan

tests/licenses_variation.rs

@@ -241,13 +241,13 @@ fn windows_target_includes_winapi_and_windows_family() {
 fn non_windows_targets_do_not_include_winapi_or_windows_family() {
     for platform in [LINUX_TARGET, APPLE_TARGET] {
         let crates = third_party_crate_names(&["max-pure"], platform);
-        assert!(!crates.contains("winapi"), "{platform} must not include `winapi`",);
+        assert!(!crates.contains("winapi"), "{platform} must not include `winapi`");
         assert!(
             !crates.contains("winapi-util"),
             "{platform} must not include `winapi-util`",
         );
         let has_windows_family = crates.iter().any(|n| n == "windows" || n.starts_with("windows-"));
-        assert!(!has_windows_family, "{platform} must not include any `windows*` crate",);
+        assert!(!has_windows_family, "{platform} must not include any `windows*` crate");
     }
 }
 
@@ -273,7 +273,7 @@ fn non_apple_targets_do_not_include_security_framework() {
     for platform in [LINUX_TARGET, WINDOWS_TARGET] {
         let crates = third_party_crate_names(&["max-pure"], platform);
         for forbidden in ["security-framework", "security-framework-sys"] {
-            assert!(!crates.contains(forbidden), "{platform} must not include `{forbidden}`",);
+            assert!(!crates.contains(forbidden), "{platform} must not include `{forbidden}`");
         }
     }
 }

tests/licenses_workspace_attribution.rs

@@ -311,7 +311,7 @@ fn every_workspace_member_with_different_attribution_is_in_manifest() {
         // independent of any license parser bug, so this direction admits
         // no excuse.
         if author_differs && !in_full {
-            missing_despite_author_diff.push(format!("{name} (authors {pkg_authors:?} vs root {root_authors:?})",));
+            missing_despite_author_diff.push(format!("{name} (authors {pkg_authors:?} vs root {root_authors:?})"));
             continue;
         }