Docs: Directory Structure content suggestions

[marissahuysentruyt]

Some minor content suggestions to clarify.

FROM:

...which is documented in the [configuration page]

TO:

...which is documented on the [configuration page]

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FROM:

Catalysts are what power your design system, in this folder is where you store your components and other partials.

TO:

Catalysts are what power your design system. This folder is where you store your components and other partials.

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FROM:

A few start TypeScript files can be found here.

TO:

A few starting TypeScript files can be found in this directory.

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• spelling correction: 'verbatuim' to 'verbatim'

• Should we include a link to ITCSS?

FROM:

Here is where to place your styles. Propulsion provides a starter BEM + Inverted Triangle Sass Architecture...

TO:

Here is where you place your styles. Propulsion provides a starter BEM + Inverted Triangle Sass architecture...