Relative links in READMEs are broken on deno.land/x

While checking out the READMEs of various libraries on deno.land/x, I've found a recurring problem with relative links.

For instance, the link to `/docs/examples` in [pup@1.0.0-rc.0](https://deno.land/x/pup@1.0.0-rc.0) incorrectly leads to https://cdn.deno.land/docs/examples instead of the expected location (directory listing).

Moreover, in the case of the [Danet README](https://github.com/Savory/Danet/blob/cf3ccfbce19165a82a9c29b7329cddef4291a3dd/README.md?plain=1#L61), a link that should point to `CONTRIBUTING.md` instead incorrectly points to https://cdn.deno.land/CONTRIBUTING.md when viewed from [danet@1.8.0](https://deno.land/x/danet@1.8.0).

Relative links in READMEs are quite common, as GitHub links lead to GitHub, n**-links lead to n**, deno.land links lead to deno.land, etc.

To clarify, my expectations for different relative path cases are as follows:

- `./CONTRIBUTING.md` -> `https://deno.land/x/package@version/CONTRIBUTING.md` (including dot, relative to the current directory)
- `/CONTRIBUTING.md` -> `https://deno.land/x/package@version/CONTRIBUTING.md` (excluding dot, relative to the repository root)
- `CONTRIBUTING.md` -> `https://deno.land/x/package@version/CONTRIBUTING.md` (excluding path, implicitly relative to current directory)
- `./contributing.md` -> `https://deno.land/x/package@version/CONTRIBUTING.md` (case insensitivity)
- `./docs/examples` -> `https://deno.land/x/package@version/docs/examples` (directory listing)