bring back plural 'alternatives' in suggestion message

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -2961,7 +2961,7 @@ pub(crate) fn maybe_recover_unexpected_comma(
         if let CommaRecoveryMode::EitherTupleOrPipe = rt {
             err.span_suggestion(
                 comma_span,
-                "...or a vertical bar to match on alternative",
+                "...or a vertical bar to match on alternatives",
                 " |",
                 Applicability::MachineApplicable,
             );

tests/ui/did_you_mean/issue-48492-tuple-destructure-missing-parens.stderr

@@ -32,7 +32,7 @@ help: try adding parentheses to match on a tuple...
    |
 LL |         (Nucleotide::Adenine, Nucleotide::Cytosine, _) => true
    |         +                                            +
-help: ...or a vertical bar to match on alternative
+help: ...or a vertical bar to match on alternatives
    |
 LL -         Nucleotide::Adenine, Nucleotide::Cytosine, _ => true
 LL +         Nucleotide::Adenine | Nucleotide::Cytosine, _ => true

tests/ui/feature-gates/feature-gate-never_patterns.stderr

@@ -8,7 +8,7 @@ help: try adding parentheses to match on a tuple...
    |
 LL |         (Some(_),)
    |         +        +
-help: ...or a vertical bar to match on alternative
+help: ...or a vertical bar to match on alternatives
    |
 LL -         Some(_),
 LL +         Some(_) |

tests/ui/parser/match-arm-without-body.stderr

@@ -16,7 +16,7 @@ help: try adding parentheses to match on a tuple...
    |
 LL |         (Some(_),)
    |         +        +
-help: ...or a vertical bar to match on alternative
+help: ...or a vertical bar to match on alternatives
    |
 LL -         Some(_),
 LL +         Some(_) |
@@ -36,7 +36,7 @@ LL |
 LL |
 LL ~         _) => {}
    |
-help: ...or a vertical bar to match on alternative
+help: ...or a vertical bar to match on alternatives
    |
 LL -         Some(_),
 LL +         Some(_) |

tests/ui/suggestions/only-replace-intended-coma-not-all-in-pattern.stderr

@@ -8,7 +8,7 @@ help: try adding parentheses to match on a tuple...
    |
 LL |         (Foo { x: 2, ch: ',' }, Foo { x: 3, ch: '@' }) => (),
    |         +                                            +
-help: ...or a vertical bar to match on alternative
+help: ...or a vertical bar to match on alternatives
    |
 LL -         Foo { x: 2, ch: ',' }, Foo { x: 3, ch: '@' } => (),
 LL +         Foo { x: 2, ch: ',' } | Foo { x: 3, ch: '@' } => (),