fix: Only show one origin for multiline annotations with no source

Author: Muscraft

compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs

@@ -633,7 +633,7 @@ impl AnnotateSnippetEmitter {
                     report.push(std::mem::replace(&mut group, Group::with_level(level.clone())));
                 }
 
-                if !line_tracker.contains(&lo.line) {
+                if !line_tracker.contains(&lo.line) && (i == 0 || hi.line <= lo.line) {
                     line_tracker.push(lo.line);
                     // ╭▸ $SRC_DIR/core/src/option.rs:594:0 (<- It adds *this*)
                     // ⸬  $SRC_DIR/core/src/option.rs:602:4

tests/ui/typeck/typeck_type_placeholder_item.stderr

@@ -688,7 +688,6 @@ note: method `filter` is not const because trait `Iterator` is not const
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
    |
    = note: this trait is not const
-  ::: $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
   ::: $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
    |
    = note: this method is not const
@@ -704,7 +703,6 @@ note: method `map` is not const because trait `Iterator` is not const
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
    |
    = note: this trait is not const
-  ::: $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
   ::: $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
    |
    = note: this method is not const