Rollup merge of #39597 - GuillaumeGomez:correct_rustdoc_test_file, r=alexcrichton

Display correct filename with --test option

Fixes #39592.

With the current files:

```rust
pub mod foo;

/// This is a Foo;
///
/// ```
/// println!("baaaaaar");
/// ```
pub struct Foo;

/// This is a Bar;
///
/// ```
/// println!("fooooo");
/// ```
pub struct Bar;
```

```rust
// note the whitespaces
/// ```
/// println!("foo");
/// ```
pub fn foo() {}
```

It displays:

```
./build/x86_64-apple-darwin/stage1/bin/rustdoc --test test.rs

running 3 tests
test test.rs - line 13 ... ok
test test.rs - line 5 ... ok
test foo.rs - line 2 ... ok

test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured
```

```

` ``
println!("lol");
` ``

asdjnfasd

asd
```

It displays:

```
./build/x86_64-apple-darwin/stage1/bin/rustdoc --test foo.md

running 1 test
test <input> - line 3 ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured
```

r? @alexcrichton

2 files changed, 21 insertions, 0 deletions

diff --git a/src/test/rustdoc/test_option_check/bar.rs b/src/test/rustdoc/test_option_check/bar.rs
new file mode 100644
index 00000000000..51daa807526
--- /dev/null
+++ b/src/test/rustdoc/test_option_check/bar.rs
@@ -0,0 +1,19 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags: --test
+// check-test-line-numbers-match
+
+/// This looks like another awesome test!
+///
+/// ```
+/// println!("foo?");
+/// ```
+pub fn foooo() {}
diff --git a/src/test/rustdoc/test_option_check/test.rs b/src/test/rustdoc/test_option_check/test.rs
index b2afe43204d..a9578c5f434 100644
--- a/src/test/rustdoc/test_option_check/test.rs
+++ b/src/test/rustdoc/test_option_check/test.rs
@@ -11,6 +11,8 @@
 // compile-flags: --test
 // check-test-line-numbers-match
 
+pub mod bar;
+
 /// This is a Foo;
 ///
 /// ```