Fixed broken links in Readme and rust docs warning.

[BoolPurist]

Changes

• Fixed warnings previously emitted by command cargo doc.
• Fixed some spelling.
• Fixed a few links for Github in README by prefixing them with a leading "/". Without those leading slashes the links produce a file not found aka 404 error.

Note

In file bevy_asset_loader/src/dynamic_asset.rs at line 446 I replaced the link to struct which is only visible within the crate, with just the word state. This change fixes a warning produced by the command:

cargo doc --all-features

and prevents leaking an inner detail which is not relevant to an user of the crate.

[NiklasEi]

Hey, thank you 🙂
The readme links without leading slash were an experiment for #113, but I clearly forgot that you can read the Readme on the base of the repository (here the links work) and in the bevy_asset_loader directory (here they are broken).

[BoolPurist]

"This is actually British English vs American English. I think I prefer British (so initialise)."
Fair enough. I reverted the spelling back to British variant.

[NiklasEi]

Thanks again 🙂