Fix rustdoc test failure

Author: GuillaumeGomez

src/test/rustdoc/cap-lints.rs

@@ -13,8 +13,8 @@
 // therefore should not concern itself with the lints.
 #[deny(warnings)]
 
-// @has cap_lints/struct.foo.html //pre '#[must_use]'
+// @has cap_lints/struct.Foo.html //pre '#[must_use]'
 #[must_use]
-pub struct foo {
+pub struct Foo {
     field: i32,
 }