Remove assert to fix highlighting

Author: adpi2

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -807,7 +807,7 @@ object Parsers {
     /** When rewriting to indent, make sure there is an indent after a `=>\n` */
     def indentedRegionAfterArrow[T](body: => T, inCaseDef: Boolean = false): T =
       if in.rewriteToIndent && (inCaseDef || in.isAfterLineEnd) then
-        assert(in.last.isArrow || in.last.token == SELFARROW)
+        // assert(in.last.isArrow || in.last.token == SELFARROW)
         toIndentedRegion(body)
       else body