Improve the documentation about automatic metadata

[jalkoby]

Continuing the conversation #1541

[JonRowe]

This reads weirdly, how about To enable automatic metadata for other folders, useRSpec::Configuration#define_derived_metadata`, for an example see below:

[jalkoby]

@JonRowe I've updated the wording and change the regexp

[chrisarcand]

I see this line as rather needless as the line directly above it says that: "If you follow the above listed canonical directory structure..." And the canonical structure mentioned is the very first thing this document goes over in detail.

Perhaps we can remove this line and just change the one below to "If you want to set metadata for a custom directory that doesn't follow fit the canonical structure above, you can do the following:" ? (Note I changed folder -> directory as well, since the rest of the document uses directory, not folder. Consistency FTW!)

[JonRowe]

👍

[jalkoby]

The wording was changed. Also I found the reason of spec failing - cucumber needs a zero-length space before "#" comment symbol

[JonRowe]

Thanks ❤️

[chrisarcand]

👍 👍