Update font-family.mdx, remove quotes from generic font-family (#2323)

Author: carlcs

src/docs/font-family.mdx

@@ -78,14 +78,14 @@ Use utilities like `font-sans` and `font-mono` to set the font family of an elem
   utility="font"
   name="font family"
   customName="display"
-  customValue='"Oswald", "sans-serif"'
+  customValue='"Oswald", sans-serif'
 >
 
 You can also provide default `font-feature-settings` and `font-variation-settings` values for a font family:
 
 ```css
 @theme {
-  --font-display: "Oswald", "sans-serif";
+  --font-display: "Oswald", sans-serif;
   --font-display--font-feature-settings: "cv02", "cv03", "cv04", "cv11"; /* [!code highlight] */
   --font-display--font-variation-settings: "opsz" 32; /* [!code highlight] */
 }