test: Format strings in *.rs

`format!` strings may contain variables within the string
representation. This is a lint as of a recent `rustc` nightly version.

contrib/devtools/deterministic-fuzz-coverage/src/main.rs

@@ -36,7 +36,7 @@ fn sanity_check(corpora_dir: &Path, fuzz_exe: &Path) -> AppResult {
         let output = Command::new(tool).arg("--help").output();
         match output {
             Ok(output) if output.status.success() => {}
-            _ => Err(exit_help(&format!("The tool {} is not installed", tool)))?,
+            _ => Err(exit_help(&format!("The tool {tool} is not installed")))?,
         }
     }
     if !corpora_dir.is_dir() {
@@ -274,7 +274,7 @@ fn main() -> ExitCode {
     match app() {
         Ok(()) => ExitCode::SUCCESS,
         Err(err) => {
-            eprintln!("⚠️\n{}", err);
+            eprintln!("⚠️\n{err}");
             ExitCode::FAILURE
         }
     }

contrib/devtools/deterministic-unittest-coverage/src/main.rs

@@ -32,7 +32,7 @@ fn sanity_check(test_exe: &Path) -> AppResult {
         let output = Command::new(tool).arg("--help").output();
         match output {
             Ok(output) if output.status.success() => {}
-            _ => Err(exit_help(&format!("The tool {} is not installed", tool)))?,
+            _ => Err(exit_help(&format!("The tool {tool} is not installed")))?,
         }
     }
     if !test_exe.exists() {
@@ -142,7 +142,7 @@ fn main() -> ExitCode {
     match app() {
         Ok(()) => ExitCode::SUCCESS,
         Err(err) => {
-            eprintln!("⚠️\n{}", err);
+            eprintln!("⚠️\n{err}");
             ExitCode::FAILURE
         }
     }

test/lint/test_runner/src/main.rs

@@ -223,7 +223,7 @@ fn get_pathspecs_default_excludes() -> Vec<String> {
         .chain(&[
             "doc/release-notes/release-notes-*", // archived notes
         ])
-        .map(|s| format!(":(exclude){}", s))
+        .map(|s| format!(":(exclude){s}"))
         .collect()
 }
 
@@ -280,8 +280,7 @@ fn lint_commit_msg() -> LintResult {
         if let Some(line) = commit_info.lines().nth(1) {
             if !line.is_empty() {
                 println!(
-                        "The subject line of commit hash {} is followed by a non-empty line. Subject lines should always be followed by a blank line.",
-                        hash
+                        "The subject line of commit hash {hash} is followed by a non-empty line. Subject lines should always be followed by a blank line."
                     );
                 good = false;
             }
@@ -351,15 +350,14 @@ fn lint_py_lint() -> LintResult {
 
     match cmd.status() {
         Ok(status) if status.success() => Ok(()),
-        Ok(_) => Err(format!("`{}` found errors!", bin_name)),
+        Ok(_) => Err(format!("`{bin_name}` found errors!")),
         Err(e) if e.kind() == ErrorKind::NotFound => {
             println!(
-                "`{}` was not found in $PATH, skipping those checks.",
-                bin_name
+                "`{bin_name}` was not found in $PATH, skipping those checks."
             );
             Ok(())
         }
-        Err(e) => Err(format!("Error running `{}`: {}", bin_name, e)),
+        Err(e) => Err(format!("Error running `{bin_name}`: {e}")),
     }
 }
 
@@ -491,7 +489,7 @@ fn get_pathspecs_exclude_whitespace() -> Vec<String> {
             "test/lint/git-subtree-check.sh",
         ]
         .iter()
-        .map(|s| format!(":(exclude){}", s)),
+        .map(|s| format!(":(exclude){s}")),
     );
     list
 }
@@ -650,14 +648,13 @@ still succeed, but silently be buggy. For example, a slower fallback algorithm c
 even though bitcoin-build-config.h indicates that a faster feature is available and should be used.
 
 If you are unsure which symbol is used, you can find it with this command:
-git grep --perl-regexp '{}' -- file_name
+git grep --perl-regexp '{defines_regex}' -- file_name
 
 Make sure to include it with the IWYU pragma. Otherwise, IWYU may falsely instruct to remove the
 include again.
 
 #include <bitcoin-build-config.h> // IWYU pragma: keep
-            "#,
-            defines_regex
+            "#
         )
         .trim()
         .to_string());
@@ -714,9 +711,8 @@ One or more markdown links are broken.
 Note: relative links are preferred as jump-to-file works natively within Emacs, but they are not required.
 
 Markdown link errors found:
-{}
-                "#,
-                stderr
+{stderr}
+                "#
             )
             .trim()
             .to_string())
@@ -725,7 +721,7 @@ Markdown link errors found:
             println!("`mlc` was not found in $PATH, skipping markdown lint check.");
             Ok(())
         }
-        Err(e) => Err(format!("Error running mlc: {}", e)), // Misc errors
+        Err(e) => Err(format!("Error running mlc: {e}")), // Misc errors
     }
 }
 
@@ -744,7 +740,7 @@ fn run_all_python_linters() -> LintResult {
                 .success()
         {
             good = false;
-            println!("^---- ⚠️ Failure generated from {}", entry_fn);
+            println!("^---- ⚠️ Failure generated from {entry_fn}");
         }
     }
     if good {