Address doc comment rot in the standard library.

- Match @param/@tparam names to the actual parameter name
- Use @tparam for type parameters
- Whitespace is required between `*` and `@`
- Fix incorrect references to @define macros.
- Use of monospace `` and {{{}}} (much more needed)
- Remove `@param p1 ...` stubs, which appear in the generated docss.
  - But, retainsed `@param p1` stubs, assuming they will be filtered from
    the generated docs by SI-5795.
- Avoid use of the shorthand `@param   doc for the solitary param`
  (which works, but isn't recognized by the code inspection in IntelliJ
  I used to sweep through the problems)

The remaining warnings from `ant docs` seem spurious, I suspect they are
an unintended consequence of documenting extension methods.

  [scaladoc] /Users/jason/code/scala/src/library/scala/collection/TraversableOnce.scala:181: warning: Variable coll undefined in comment for method reduceOption in class Tuple2Zipped
  [scaladoc]   def reduceOption[A1 >: A](op: (A1, A1) => A1): Option[A1] = reduceLeftOption(op)
  [scaladoc]       ^

1 files changed, 1 insertions, 1 deletions

diff --git a/src/library/scala/Option.scala b/src/library/scala/Option.scala
index 44c8fba45f..c461b413d6 100644
--- a/src/library/scala/Option.scala
+++ b/src/library/scala/Option.scala
@@ -146,7 +146,7 @@ sealed abstract class Option[+A] extends Product with Serializable {
 
   /** Returns the result of applying $f to this $option's
    *  value if the $option is nonempty.  Otherwise, evaluates
-   *  expression $ifEmpty.
+   *  expression `ifEmpty`.
    *
    *  @note This is equivalent to `$option map f getOrElse ifEmpty`.
    *