lint: port redundant semicolons diagnostics

Signed-off-by: David Wood <david.wood@huawei.com>

Author: davidtwco

compiler/rustc_error_messages/locales/en-US/lint.ftl

@@ -131,3 +131,13 @@ lint-noop-method-call = call to `.{$method}()` on a reference in this situation
 
 lint-pass-by-value = passing `{$ty}` by reference
     .suggestion = try passing by value
+
+lint-redundant-semicolons =
+    unnecessary trailing {$multiple ->
+        [true] semicolons
+        *[false] semicolon
+    }
+    .suggestion = remove {$multiple ->
+        [true] these semicolons
+        *[false] this semicolon
+    }

compiler/rustc_lint/src/redundant_semicolon.rs

@@ -1,6 +1,6 @@
 use crate::{EarlyContext, EarlyLintPass, LintContext};
 use rustc_ast::{Block, StmtKind};
-use rustc_errors::Applicability;
+use rustc_errors::{fluent, Applicability};
 use rustc_span::Span;
 
 declare_lint! {
@@ -49,12 +49,10 @@ fn maybe_lint_redundant_semis(cx: &EarlyContext<'_>, seq: &mut Option<(Span, boo
         }
 
         cx.struct_span_lint(REDUNDANT_SEMICOLONS, span, |lint| {
-            let (msg, rem) = if multiple {
-                ("unnecessary trailing semicolons", "remove these semicolons")
-            } else {
-                ("unnecessary trailing semicolon", "remove this semicolon")
-            };
-            lint.build(msg).span_suggestion(span, rem, "", Applicability::MaybeIncorrect).emit();
+            lint.build(fluent::lint::redundant_semicolons)
+                .set_arg("multiple", multiple)
+                .span_suggestion(span, fluent::lint::suggestion, "", Applicability::MaybeIncorrect)
+                .emit();
         });
     }
 }