rename ext_tool_checks to extra_checks and use mod.rs

this makes the triagebot pings for this module simpler

Author: lolbinarycat

src/tools/tidy/src/ext_tool_checks.rs renamed to src/tools/tidy/src/extra_checks/mod.rs

@@ -165,8 +165,8 @@ pub mod debug_artifacts;
 pub mod deps;
 pub mod edition;
 pub mod error_codes;
-pub mod ext_tool_checks;
 pub mod extdeps;
+pub mod extra_checks;
 pub mod features;
 pub mod filenames;
 pub mod fluent_alphabetical;

src/tools/tidy/src/ext_tool_checks/rustdoc_js.rs renamed to src/tools/tidy/src/extra_checks/rustdoc_js.rs

@@ -177,7 +177,7 @@ fn main() {
         check!(unstable_book, &src_path, collected);
 
         check!(
-            ext_tool_checks,
+            extra_checks,
             &root_path,
             &output_directory,
             &ci_info,

src/tools/tidy/src/lib.rs

@@ -1096,7 +1096,7 @@ cc = ["@jieyouxu"]
 message = "The list of allowed third-party dependencies may have been modified! You must ensure that any new dependencies have compatible licenses before merging."
 cc = ["@davidtwco", "@wesleywiser"]
 
-[mentions."src/tools/tidy/src/ext_tool_checks.rs"]
+[mentions."src/tools/tidy/src/extra_checks"]
 message = "`tidy` extra checks were modified."
 cc = ["@lolbinarycat"]