Restore currently valid doc pages to original form

Changes should be rolled out only after released.

Author: odersky

docs/docs/reference/contextual/implicit-function-types.md

@@ -83,13 +83,13 @@ with implicit function types as parameters to avoid the plumbing boilerplate
 that would otherwise be necessary.
 ```scala
   def table(init: (given Table) => Unit) = {
-    given t as Table
+    given t: Table
     init
     t
   }
 
   def row(init: (given Row) => Unit)(given t: Table) = {
-    given r as Row
+    given r: Row
     init
     t.add(r)
   }

docs/docs/reference/contextual/import-delegate.md

@@ -7,7 +7,7 @@ A special form of import wildcard selector is used to import given instances. Ex
 ```scala
 object A {
   class TC
-  given tc as TC
+  given tc: TC
   def f(given TC) = ???
 }
 object B {
@@ -50,8 +50,8 @@ Importing all given instances of a parameterized type is expressed by wildcard a
 For instance, assuming the object
 ```scala
 object Instances {
-  given intOrd as Ordering[Int]
-  given [T as Ordering] listOrd as Ordering[List[T]]
+  given intOrd: Ordering[Int]
+  given [T: Ordering] listOrd: Ordering[List[T]]
   given ec: ExecutionContext = ...
   given im: Monoid[Int]
 }