Remove ordinalize.

Some minor (English only) heroics are performed to print error messages
like "5th rule of macro `m` is never used". The form "rule #5 of macro
`m` is never used" is just as good and much simpler to implement.

compiler/rustc_resolve/src/diagnostics.rs

@@ -44,9 +44,6 @@ use crate::{LexicalScopeBinding, NameBinding, NameBindingKind, PrivacyError, Vis
 use crate::{ParentScope, PathResult, ResolutionError, Resolver, Scope, ScopeSet};
 use crate::{Segment, UseError};
 
-#[cfg(test)]
-mod tests;
-
 type Res = def::Res<ast::NodeId>;
 
 /// A vector of spans and replacements, a message and applicability.
@@ -3027,14 +3024,3 @@ fn is_span_suitable_for_use_injection(s: Span) -> bool {
     // import or other generated ones
     !s.from_expansion()
 }
-
-/// Convert the given number into the corresponding ordinal
-pub(crate) fn ordinalize(v: usize) -> String {
-    let suffix = match ((11..=13).contains(&(v % 100)), v % 10) {
-        (false, 1) => "st",
-        (false, 2) => "nd",
-        (false, 3) => "rd",
-        _ => "th",
-    };
-    format!("{v}{suffix}")
-}