Use mod tests consistently (#5278)

As per the Rust documentation.

crates/ruff/src/jupyter/notebook.rs

@@ -445,7 +445,7 @@ impl Notebook {
 }
 
 #[cfg(test)]
-mod test {
+mod tests {
     use std::path::Path;
 
     use anyhow::Result;

crates/ruff/src/rules/pyupgrade/fixes.rs

@@ -126,7 +126,7 @@ pub(crate) fn remove_import_members(contents: &str, members: &[&str]) -> String
 }
 
 #[cfg(test)]
-mod test {
+mod tests {
     use crate::rules::pyupgrade::fixes::remove_import_members;
 
     #[test]

crates/ruff/src/rules/pyupgrade/rules/printf_string_formatting.rs

@@ -477,7 +477,7 @@ pub(crate) fn printf_string_formatting(
 }
 
 #[cfg(test)]
-mod test {
+mod tests {
     use test_case::test_case;
 
     use super::*;

crates/ruff_cli/src/cache.rs

@@ -299,7 +299,7 @@ pub(crate) fn init(path: &Path) -> Result<()> {
 }
 
 #[cfg(test)]
-mod test {
+mod tests {
     use std::env::temp_dir;
     use std::fs;
     use std::io::{self, Write};

crates/ruff_cli/src/diagnostics.rs

@@ -346,7 +346,7 @@ pub(crate) fn lint_stdin(
 }
 
 #[cfg(test)]
-mod test {
+mod tests {
     use std::path::Path;
 
     use crate::diagnostics::{load_jupyter_notebook, Diagnostics};

crates/ruff_dev/src/generate_cli_help.rs

@@ -119,7 +119,7 @@ fn check_help_text() -> String {
 }
 
 #[cfg(test)]
-mod test {
+mod tests {
     use anyhow::Result;
 
     use crate::generate_all::Mode;

crates/ruff_dev/src/generate_json_schema.rs

@@ -53,7 +53,7 @@ pub(crate) fn main(args: &Args) -> Result<()> {
 }
 
 #[cfg(test)]
-mod test {
+mod tests {
     use anyhow::Result;
     use std::env;