Reword confusable idents lint

Fix #76140.

Author: estebank

compiler/rustc_lint/messages.ftl

@@ -166,8 +166,9 @@ lint_check_name_warning = {$msg}
 
 lint_command_line_source = `forbid` lint level was set on command line
 
-lint_confusable_identifier_pair = identifier pair considered confusable between `{$existing_sym}` and `{$sym}`
-    .label = this is where the previous identifier occurred
+lint_confusable_identifier_pair = found both `{$existing_sym}` and `{$sym}` as identifiers, which look alike
+    .current_use = this identifier can be confused with `{$existing_sym}`
+    .other_use = other identifier used here
 
 lint_cstring_ptr = getting the inner pointer of a temporary `CString`
     .as_ptr_label = this pointer will be invalid

compiler/rustc_lint/src/lints.rs

@@ -1056,8 +1056,10 @@ pub struct IdentifierUncommonCodepoints;
 pub struct ConfusableIdentifierPair {
     pub existing_sym: Symbol,
     pub sym: Symbol,
-    #[label]
+    #[label(lint_other_use)]
     pub label: Span,
+    #[label(lint_current_use)]
+    pub main_label: Span,
 }
 
 #[derive(LintDiagnostic)]

compiler/rustc_lint/src/non_ascii_idents.rs

@@ -222,6 +222,7 @@ impl EarlyLintPass for NonAsciiIdents {
                                     existing_sym: *existing_symbol,
                                     sym: symbol,
                                     label: *existing_span,
+                                    main_label: sp,
                                 },
                             );
                         }

tests/ui/lint/rfc-2457-non-ascii-idents/lint-confusable-idents.rs

@@ -5,8 +5,8 @@ const ｓ: usize = 42;
 const s_s: usize = 42;
 
 fn main() {
-    let s = "rust"; //~ ERROR identifier pair considered confusable
-    let ｓ_ｓ = "rust2"; //~ ERROR identifier pair considered confusable
+    let s = "rust"; //~ ERROR found both
+    let ｓ_ｓ = "rust2"; //~ ERROR found both
     not_affected();
 }
 

tests/ui/lint/rfc-2457-non-ascii-idents/lint-confusable-idents.stderr

@@ -1,26 +1,26 @@
-error: identifier pair considered confusable between `ｓ` and `s`
+error: found both `ｓ` and `s` as identifiers, which look alike
   --> $DIR/lint-confusable-idents.rs:8:9
    |
 LL | const ｓ: usize = 42;
-   |       -- this is where the previous identifier occurred
+   |       -- other identifier used here
 ...
 LL |     let s = "rust";
-   |         ^
+   |         ^ this identifier can be confused with `ｓ`
    |
 note: the lint level is defined here
   --> $DIR/lint-confusable-idents.rs:1:9
    |
 LL | #![deny(confusable_idents)]
    |         ^^^^^^^^^^^^^^^^^
 
-error: identifier pair considered confusable between `s_s` and `ｓ_ｓ`
+error: found both `s_s` and `ｓ_ｓ` as identifiers, which look alike
   --> $DIR/lint-confusable-idents.rs:9:9
    |
 LL | const s_s: usize = 42;
-   |       --- this is where the previous identifier occurred
+   |       --- other identifier used here
 ...
 LL |     let ｓ_ｓ = "rust2";
-   |         ^^^^^
+   |         ^^^^^ this identifier can be confused with `s_s`
 
 error: aborting due to 2 previous errors