[css-shadow-parts] Spell check.

Author: dbaron

css-shadow-parts/Overview.bs

@@ -47,7 +47,7 @@ into the component for it to do with as it will,
 these pseudo-elements allow components and the outside page
 to interact in safe, powerful ways,
 maintaining encapsulation
-without surrending all control.
+without surrendering all control.
 
 Motivation {#motivation}
 ------------------------