Rollup merge of #72180 - euclio:rustdoc-test-extra-space, r=Dylan-DPC

remove extra space from crate-level doctest names

Before:

```
running 2 tests
test src/test/rustdoc-ui/doctest-output.rs - foo::bar (line 11) ... ok
test src/test/rustdoc-ui/doctest-output.rs -  (line 5) ... ok

test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
```

After:

```
running 2 tests
test src/test/rustdoc-ui/doctest-output.rs - foo::bar (line 11) ... ok
test src/test/rustdoc-ui/doctest-output.rs - (line 5) ... ok

test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
```

Author: Dylan-DPC

src/librustdoc/test.rs

@@ -676,7 +676,11 @@ impl Collector {
     }
 
     fn generate_name(&self, line: usize, filename: &FileName) -> String {
-        format!("{} - {} (line {})", filename, self.names.join("::"), line)
+        let mut item_path = self.names.join("::");
+        if !item_path.is_empty() {
+            item_path.push(' ');
+        }
+        format!("{} - {}(line {})", filename, item_path, line)
     }
 
     pub fn set_position(&mut self, position: Span) {

src/test/rustdoc-ui/doctest-output.rs

@@ -0,0 +1,15 @@
+// compile-flags:--test --test-args=--test-threads=1
+// normalize-stdout-test: "src/test/rustdoc-ui" -> "$$DIR"
+// check-pass
+
+//! ```
+//! assert_eq!(1 + 1, 2);
+//! ```
+
+pub mod foo {
+
+    /// ```
+    /// assert_eq!(1 + 1, 2);
+    /// ```
+    pub fn bar() {}
+}

src/test/rustdoc-ui/doctest-output.stdout

@@ -0,0 +1,7 @@
+
+running 2 tests
+test $DIR/doctest-output.rs - (line 5) ... ok
+test $DIR/doctest-output.rs - foo::bar (line 11) ... ok
+
+test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
+