Update docs and change exception

Author: nicolasstucki

compiler/src/dotty/tools/dotc/quoted/Toolbox.scala

@@ -25,7 +25,7 @@ object Toolbox {
       case expr: LiftedExpr[T] =>
         expr.value
       case expr: TastyTreeExpr[Tree] @unchecked =>
-        throw new scala.quoted.QuoteError("Can't run and scala.quoted.Expr coming from a macro argument")
+        throw new Exception("Cannot call `Expr.run` on an `Expr` that comes from an inline macro argument.")
       case _ =>
         new QuoteDriver().run(expr, runSettings)
     }

library/src/scala/quoted/Expr.scala

@@ -48,7 +48,7 @@ object Exprs {
    *  These expressions are used for arguments of inline macros. They contain and actual tree
    *  from the program that is being expanded by the macro.
    *
-   *  May contain references to code defined outside this Expr instance.
+   *  May contain references to code defined outside this TastyTreeExpr instance.
    */
   final class TastyTreeExpr[Tree](val tree: Tree) extends quoted.Expr[Any] {
     override def toString: String = s"Expr(<tasty tree>)"