build(aio): improve the API Pipe pages (#22702)

This change adds:

* an impure badge for Pipes that are marked as  `pure: false`
* a pipe specific overview that shows the syntax for using a pipe in a template.
* an "input value" section describing the type of the value that the pipe expects.
* a "pipe params" section describing any additional params that a pipe expects.

PR Close #22702

aio/src/styles/2-modules/_label.scss

@@ -48,6 +48,10 @@ label.raised, .api-header label {
 
     &.api-status-label {
         background-color: $mediumgray;
+
+        &.impure-pipe {
+            background-color: $brightred;
+        }
     }
 
     &.api-type-label {