feat(docs): batch 13 of proofread docs

[vwheeler63]

• freetype.rst [link]
• font_manager.rst [link]

No significant re-writing in this batch, and no code modifications.

cc: @kisvegabor @liamHowatt

Notes

• Update the Documentation if needed. Done.
• Add Examples if relevant. n/a
• Add Tests if applicable. n/a
• If you added new options to lv_conf_template.h run lv_conf_internal_gen.py and update Kconfig. n/a
• Run scripts/code-format.py (astyle v3.4.12 needs to installed by running cd scripts; ./install_astyle.sh) and follow the Code Conventions. n/a
• Mark the Pull request as Draft while you are working on the first version, and mark is as Ready when it's ready for review. Done.
• When changes were requested, re-request review to notify the maintainers. Done.
• Help us to review this Pull Request! Anyone can approve or request changes.

[kisvegabor]

Thank you!