Fix typo in documentation

Author: yilinwei

library/src/scala/quoted/ScopeException.scala

@@ -1,4 +1,4 @@
 package scala.quoted
 
-/** Excetion thrown when an Expr or Type is used ouside of the scope where it is valid */
+/** Exception thrown when an Expr or Type is used ouside of the scope where it is valid */
 class ScopeException(msg: String) extends Exception(msg)