fix links within the readme of non-components (e.g. libraries such as o-errors)

[notlee]

Links within the readme of non-component's may be broken.
The registry replaces any relative links within a readme to source code / files
with an absolute link to Github. To do so the registry assumes understanding of
the financial-times/origami repository's directory structure – and gets that wrong
for non-components.

It assumes all projects live under the components directory within the mono repo.
Some projects such as tools live under the tools directory. Other projects such as libraries
live under the libraries directory.
https://github.com/Financial-Times/origami/tree/${component.name}-v${component.version}/components/${component.name}.
https://github.com/Financial-Times/origami-registry-ui/blob/master/lib/code-docs/readme/index.js#L20

E.g. the migration guide links in the o-errors readme link to:
https://github.com/Financial-Times/origami/tree/o-errors-v5.2.2/components/o-errors/MIGRATION.md#migrating-from-v4-to-v5
instead of:
https://github.com/Financial-Times/origami/tree/o-errors-v5.2.2/libraries/o-errors/MIGRATION.md#migrating-from-v4-to-v5