fix(website): change title case guideline to sentence case (#3966)

* fix(website): change title case guideline to sentence case

* feat(internal docs): add more icon request guidelines

internal-docs/process/icon-requests.md

@@ -2,7 +2,10 @@
 You're in helper duty and there is a new icon request on GitHub:
 * Read the request and review the needed icon(s).
 * Make sure the requested icon is suitable to be part of Paste library:
-  * If the requester is external to Twilio, determine whether the icon is generic enough to be used by other teams at Twilio. If it's not generic, you can point them to the [SVG-to-React library](https://paste.twilio.design/core/libraries), which allows them to create a React component with their SVG.
+  * The requester is a Twilio employee.
+    * If the requester is external, determine whether the icon is generic enough to be used by other teams at Twilio. If it's not generic, you can point them to the [SVG-to-React library](https://paste.twilio.design/core/libraries), which allows them to create a React component with their SVG.
+  * It is not a 3rd party branded icon.
+    * Explain that we don't add 3rd party logos because most brands have strict usage guidelines around color and clearspace for their logos that we want to make sure teams thoughtfully apply and manage those assets for their own use cases. And some also have distribution restrictions.
   * It doesn’t already exist or is too similar to an existing one
     * If it exists, you can suggest using the current one or ask to explain why a different one is needed.
     * If it's too similar, you can propose other options using [Streamline](https://www.streamlinehq.com/icons/legacy-streamline-regular) and share it in the Github discussion.

packages/paste-website/src/pages/foundations/typography/index.mdx

@@ -550,9 +550,9 @@ We recommend avoiding forced capitalization. It’s not accessible with scre
   alt="do: use sentence casing in general UI; don't: use all caps unless absolutely necessary"
 />
 
-#### In almost all cases in Twilio, use title case
+#### In almost all cases in Twilio, use sentence case
 
-More tips on when to not capitalize:
+Tips on when and when not to capitalize:
 
 - Avoid setting a single capitalization design rule that fits all languages.
 - In French, Italian, and Spanish (among others) only the first letter should be capitalized for certain words.
@@ -562,7 +562,7 @@ Developers should avoid using CSS, e.g. text-transform: capitalize; to handle ca
 
 [Read about capitalization and more on our localization page.](/foundations/localization/#avoid-forced-capitalization)
 
-Here’s when you do capitalize:
+Here’s when you do capitalize every word with title case:
 
 - Proper nouns – products, people, places.
 - Products include features, programs, or systems that Twilio has given a specific name to.