Add test for doc comments unindent fix

src/test/rustdoc/unindent.rs

@@ -0,0 +1,23 @@
+#![crate_name = "foo"]
+
+// @has foo/struct.Example.html
+// @matches - '//pre[@class="rust rust-example-rendered"]' \
+//     '(?m)let example = Example::new\(\)\n    \.first\(\)\n    \.second\(\)\n    \.build\(\);\Z'
+/// ```rust
+/// let example = Example::new()
+///     .first()
+#[cfg_attr(not(feature = "one"), doc = "    .second()")]
+///     .build();
+/// ```
+pub struct Example;
+
+// @has foo/struct.F.html
+// @matches - '//pre[@class="rust rust-example-rendered"]' \
+//     '(?m)let example = Example::new\(\)\n    \.first\(\)\n    \.another\(\)\n    \.build\(\);\Z'
+///```rust
+///let example = Example::new()
+///    .first()
+#[cfg_attr(not(feature = "one"), doc = "    .another()")]
+///    .build();
+/// ```
+pub struct F;