fix some links

Author: steveklabnik

_posts/2017-02-02-Rust-1.15.md

@@ -99,7 +99,7 @@ fn main() {
 }
 ```
 
-For full instructions, see [the website][diesel].
+For full instructions, see [the website][Diesel].
 
 These kinds of libraries are extremely powerful, but rely on custom derive for
 ergonomics. While these libraries _worked_ on Rust stable previously, they were
@@ -234,7 +234,7 @@ check what your packages are doing and update to use `std::env`!
 
 [cargo/3368]:  https://github.com/rust-lang/cargo/pull/3368
 
-The `cargo test` command has [gained support for a `--all` flag][cargo/3221],
+The `cargo test` command has [gained support for a `--all` flag][cargo/3321],
 which is useful when you have a workspace.
 
 [cargo/3321]: https://github.com/rust-lang/cargo/pull/3321