Remove outdated warnings about links from docs

Signed-off-by: Aanand Prasad <[email protected]>

docs/compose-file.md

@@ -808,7 +808,7 @@ future Compose release.
 
 Version 1 files cannot declare named
 [volumes](#volume-configuration-reference), [networks](networking.md) or
-[build arguments](#args). They *can*, however, define [links](#links).
+[build arguments](#args).
 
 Example:
 
@@ -837,10 +837,6 @@ Named [volumes](#volume-configuration-reference) can be declared under the
 `volumes` key, and [networks](#network-configuration-reference) can be declared
 under the `networks` key.
 
-You cannot define links when using version 2. Instead, you should use
-[networking](networking.md) for communication between containers. In most cases,
-this will involve less configuration than links.
-
 Simple example:
 
     version: 2