Rollup merge of #144657 - Muscraft:fix-unicode-close-window, r=fee1-dead

fix: Only "close the window" when its the last annotated file

While comparing the Unicode theme output of `rustc` and `annotate-snippets`, I found that `rustc` would ["close the window"](https://github.com/rust-lang/rust/blob/686bc1c5f9c06762b18082434c04d514acf6707e/compiler/rustc_errors/src/emitter.rs#L1025-L1027) (draw a `╰╴`), even though there were other annotated files that followed the current one. This PR makes it so the emitter will only "close the window" on the last annotated file.

Before:
```
error[E0624]: method `method` is private
   ╭▸ $DIR/close_window.rs:9:7
   │
LL │     s.method();
   ╰╴      ━━━━━━ private method
   │
   ⸬ $DIR/auxiliary/close_window.rs:3:5
   │
LL │     fn method(&self) {}
   ╰╴    ──────────────── private method defined here
```

After:
```
error[E0624]: method `method` is private
   ╭▸ $DIR/close_window.rs:9:7
   │
LL │     s.method();
   │       ━━━━━━ private method
   │
   ⸬ $DIR/auxiliary/close_window.rs:3:5
   │
LL │     fn method(&self) {}
   ╰╴    ──────────────── private method defined here
```

4 files changed, 43 insertions, 0 deletions

diff --git a/tests/ui/error-emitter/auxiliary/close_window.rs b/tests/ui/error-emitter/auxiliary/close_window.rs
new file mode 100644
index 00000000000..e41313b6ab3
--- /dev/null
+++ b/tests/ui/error-emitter/auxiliary/close_window.rs
@@ -0,0 +1,4 @@
+pub struct S;
+impl S {
+    fn method(&self) {}
+}
diff --git a/tests/ui/error-emitter/close_window.ascii.stderr b/tests/ui/error-emitter/close_window.ascii.stderr
new file mode 100644
index 00000000000..e208b709393
--- /dev/null
+++ b/tests/ui/error-emitter/close_window.ascii.stderr
@@ -0,0 +1,14 @@
+error[E0624]: method `method` is private
+  --> $DIR/close_window.rs:9:7
+   |
+LL |     s.method();
+   |       ^^^^^^ private method
+   |
+  ::: $DIR/auxiliary/close_window.rs:3:5
+   |
+LL |     fn method(&self) {}
+   |     ---------------- private method defined here
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0624`.
diff --git a/tests/ui/error-emitter/close_window.rs b/tests/ui/error-emitter/close_window.rs
new file mode 100644
index 00000000000..879507c287a
--- /dev/null
+++ b/tests/ui/error-emitter/close_window.rs
@@ -0,0 +1,11 @@
+//@ aux-build:close_window.rs
+//@ revisions: ascii unicode
+//@[unicode] compile-flags: -Zunstable-options --error-format=human-unicode
+
+extern crate close_window;
+
+fn main() {
+   let s = close_window::S;
+    s.method();
+   //[ascii]~^ ERROR method `method` is private
+}
diff --git a/tests/ui/error-emitter/close_window.unicode.stderr b/tests/ui/error-emitter/close_window.unicode.stderr
new file mode 100644
index 00000000000..56ab6daa278
--- /dev/null
+++ b/tests/ui/error-emitter/close_window.unicode.stderr
@@ -0,0 +1,14 @@
+error[E0624]: method `method` is private
+   ╭▸ $DIR/close_window.rs:9:7
+   │
+LL │     s.method();
+   │       ━━━━━━ private method
+   │
+   ⸬ $DIR/auxiliary/close_window.rs:3:5
+   │
+LL │     fn method(&self) {}
+   ╰╴    ──────────────── private method defined here
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0624`.