Fix postfixOps usages in build

Author: odersky

compiler/test/dotty/tools/repl/TabcompleteTests.scala

@@ -176,7 +176,7 @@ class TabcompleteTests extends ReplTest {
                      |  case dot_product_*
                      |  case __system
                      |
-                     |Foo."""stripMargin))
+                     |Foo.""".stripMargin))
   }
 
 
@@ -192,7 +192,7 @@ class TabcompleteTests extends ReplTest {
                      |  case dot_product_*
                      |  case __system
                      |
-                     |Foo.`bac"""stripMargin))
+                     |Foo.`bac""".stripMargin))
   }
 
   @Test def commands = initially {

scaladoc/src/dotty/tools/scaladoc/tasty/comments/wiki/Parser.scala

@@ -461,7 +461,7 @@ final class Parser(
       stack.length > 0 && char != endOfText
     }) do {}
 
-    list mkString
+    list.mkString
   }
 
   def getInline(isInlineEnd: => Boolean, textTransform: String => String = identity): Inline = {