toml anchor link within github is incorrect

[katamaritaco]

Within the table of contents at the top of README.md, 'toml = "0.2.1"' is supposed to link to 'https://github.com/brson/stdx#toml', but it instead links to 'https://docs.rs/toml/0.2.1/toml'.

I spent a few minutes trying to figure out why it does that, as the markdown appears to be consistent, but I couldn't find the culprit.

[brson]

Fixed. Thanks for the report @katamaritaco