Docs refer to non-existent derive(Saveload) instead of derive(ConvertSaveload)

[Kawzeg]

Description

The ConvertSaveload doc references #[derive(Saveload)], which should be #[derive(ConvertSaveload)] (see https://github.com/amethyst/specs/pull/460/files#diff-822e080d915774f7d11cc2c5bd503bffR84)

Meta

Rust version: cargo 1.39.0 (1c6ec66d5 2019-09-30)
Specs version / commit: 0.15.1 / master commit c182a28
Operating system: linux

Reproduction

Steps to reproduce the behavior:

1. Go to the specs project root directory
2. Run grep -rnw . -e 'derive(Saveload)'
3. See places using the wrong name

Expected behavior

The documentation should show derive(ConvertSaveload) instead.