Some diacritcs don't render properly in PDF exports

[alexdryden]

Description

In PDF Export, certain diacritics (breve and macron) render in a fallback font when used in front matter and chapter titles

Steps to Reproduce

1. Create a book with breve and ceron diacritical marks that will appear on the title page and chapter titles. Example: testing testinğ testğing; Music, Place, and the Sacred: Analyzing Qasīda-khonī in Understanding Place
2. Export to PDF using Prince

Expected behavior:
Letters with diacritical marks should render in the same font as surrounding letters without diacritical marks, as they do in the body of the text.

Actual behavior:

[alexdryden]

It doesn't appear that any of these fonts are dynamically generated or downloaded as part of a build process. I fixed this by manually replacing the Cormorant Garamond .ttf files in pressbooks-book/assets/book/typography/fonts with static files I downloaded from Google Fonts, which I found via the Cormorant Typeface Project's README. Let me know if you will accept this fix as a pull request into the pressbooks-book repo. The readme-fonts.txt should probably also be updated.

[SteelWagstaff]

@alexdryden yes, please. I think we probably have an old version of Cormorant Garamond that doesn't include the expected glyphs in that repo. PR would be welcomed there.

[alexdryden]

@SteelWagstaff pr submitted, thanks.