chore: Fix markdown lints

Author: jhg

README.md

@@ -1,18 +1,21 @@
 # opaque-pointer-rs
+
 Generic functions to work with opaque pointers when use FFI to expose Rust structs
 
 [![Crates.io](https://img.shields.io/crates/v/opaque-pointer)](https://crates.io/crates/opaque-pointer)
 [![Crates.io](https://img.shields.io/crates/l/opaque-pointer)](https://unlicense.org/)
-[![Crates.io](https://img.shields.io/crates/d/opaque-pointer)]()
+[![Crates.io](https://img.shields.io/crates/d/opaque-pointer)](.)
 
 ## Basic usage
+
 With this crate you can manage raw pointers easily to expose structs that will be
  use as opaque pointers from C or C++ calling to Rust functions to use it. This
  can be used with [cbindgen](https://crates.io/crates/cbindgen) crate with option `parse.parse_deps = true` for it will
  generate opaque C/C++ structs to use pointers in the arguments. You can find
  more information in [The Rust FFI Omnibus objects section](http://jakegoulding.com/rust-ffi-omnibus/objects/) of Jake Goulding.
 
 Example:
+
 ```rust
 struct TestIt {
     value: u8,