Add Note About using Neutraface Welcome Mat Heading font to docs page

[kwilloughby-sf]

Internal Salesforce teams should use the Neutraface Display Tilting font instead of the Salesforce Sans font for the Welcome Mat title text (slds-welcome-mat__info-title). Teams can request the font files from @interactivellama or @kwilloughby-sf.

General information on the font is available here: https://houseind.com/hi/neutraface

[interactivellama]

This would go in the comment section above the class declaration.