Remove deprecated docs and links to them (#1)

* Use new links 

Right now, there are multiple features with links that just say "The contents of this page have moved." It'd be more convenient if the links directly went to the updated pages.

* Delete implicit-function-types-spec.md

* Delete implicit-function-types.md

* Delete delegates.md

* Delete given-clauses.md

* Update features-classification.md

Author: ysthakur

docs/_includes/features.html

@@ -21,19 +21,19 @@ <h1 id="so-features">So, features?</h1>
                         <td>Implemented</td>
                     </tr>
                     <tr>
-                        <td><a href="https://dotty.epfl.ch/docs/reference/contextual/implicit-function-types.html">Context query</a></td>
+                        <td><a href="https://dotty.epfl.ch/docs/reference/contextual/context-functions.html">Context query</a></td>
                         <td>Implemented</td>
                     </tr>
                     <tr>
                         <td><a href="https://dotty.epfl.ch/docs/reference/other-new-features/trait-parameters.html">Trait parameters</a></td>
                         <td>Implemented</td>
                     </tr>
                     <tr>
-                        <td><a href="https://dotty.epfl.ch/docs/reference/contextual/delegates.html">Implied Instances</a></td>
+                        <td><a href="https://dotty.epfl.ch/docs/reference/contextual/givens.html">Implied Instances</a></td>
                         <td>Implemented</td>
                     </tr>
                     <tr>
-                        <td><a href="https://dotty.epfl.ch/docs/reference/contextual/given-clauses.html">Inferable parameters</a></td>
+                        <td><a href="https://dotty.epfl.ch/docs/reference/contextual/using-clauses.html">Inferable parameters</a></td>
                         <td>Implemented</td>
                     </tr>
                     <tr>

docs/docs/reference/contextual/delegates.md

@@ -20,7 +20,7 @@ These new constructs directly model core features of DOT, higher-kinded types, a
  - [Union types](new-types/union-types.md),
  - [Type lambdas](new-types/type-lambdas.md),
  replacing encodings using structural types and type projection.
- - [Implicit Function Types](contextual/implicit-function-types.md) offering abstraction over given parameters.
+ - [Context Functions](contextual/context-functions.md) offering abstraction over given parameters.
 
 **Status: essential**
 
@@ -199,4 +199,4 @@ Some existing programs will break and, given the complex nature of type inferenc
 
 In our experience, macros and changes in type and implicit argument inference together cause the large majority of problems encountered when porting existing code to Scala 3. The latter source of problems could be addressed systematically by a tool that added all inferred types and implicit arguments to a Scala 2 source code file. Most likely such a tool would be implemented as a Scala 2 compiler plugin. The resulting code would have a greatly increased likelihood to compile under Scala 3, but would often be bulky to the point of being unreadable. A second part of the rewriting tool should then selectively and iteratively remove type and implicit annotations that were synthesized by the first part as long as they compile under Scala 3. This second part could be implemented as a program that invokes the Scala 3 compiler `scalac` programmatically.
 
-Several people have proposed such a tool for some time now. I believe it is time we find the will and the resources to actually implement it.
+Several people have proposed such a tool for some time now. I believe it is time we find the will and the resources to actually implement it.