Adapt gix-config tests to changes in tempfile

`tempfile` version 3.20.0 introduces the clearer name
`TempDir::keep()` for `TempDir::into_path()`, deprecating the
latter.

This commit changes calls in `gix-config` tests to use `keep()`,
fixing new `clippy` errors.

Author: EliahKagan

gix-config/tests/config/file/init/from_paths/includes/conditional/gitdir/util.rs

@@ -143,7 +143,7 @@ pub fn assert_section_value(
             None => None,
         },
         "gix-config disagrees with the expected value, {} for debugging",
-        env.tempdir.into_path().display()
+        env.tempdir.keep().display()
     );
     assure_git_agrees(expected, env)
 }
@@ -173,7 +173,7 @@ fn assure_git_agrees(expected: Option<Value>, env: GitEnv) -> crate::Result {
         expected.is_some(),
         "{:?}, {} for debugging",
         output,
-        env.tempdir.into_path().display()
+        env.tempdir.keep().display()
     );
     let git_output: BString = output.stdout.trim_end().into();
     assert_eq!(
@@ -184,7 +184,7 @@ fn assure_git_agrees(expected: Option<Value>, env: GitEnv) -> crate::Result {
             None => "",
         },
         "git disagrees with gix-config, {:?} for debugging",
-        env.tempdir.into_path()
+        env.tempdir.keep()
     );
     Ok(())
 }

gix-config/tests/config/file/init/from_paths/includes/conditional/onbranch.rs

@@ -265,7 +265,7 @@ value = branch-override-by-include
                 dir,
                 gix_testtools::tempfile::TempDir::new().expect("substitute can be created"),
             );
-            dir.into_path()
+            dir.keep()
         }
     );
 
@@ -290,7 +290,7 @@ fn assure_git_agrees(expected: Value, dir: &mut gix_testtools::tempfile::TempDir
             dir,
             gix_testtools::tempfile::TempDir::new().expect("substitute can be created"),
         );
-        dir.into_path()
+        dir.keep()
     };
     assert!(
         output.status.success(),