rollup merge of #19492: steveklabnik/remove_outdated_comment

https://github.com/rust-lang/rust/pull/19472#issuecomment-65370278

/cc @alexcrichton

diff --cc src/libsyntax/feature_gate.rs
index 5ece63fd48d696594cd5bab002fab6791d1befdc,5d984678b7f7f492898d438160e16aa5cc196a32..11c65d531f6fd07f39625d657ab8273b299ff76f
--- 1/src/libsyntax/feature_gate.rs
--- 2/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@@ -70,11 -68,9 +68,9 @@@ static KNOWN_FEATURES: &'static [(&'sta
      ("visible_private_types", Active),
      ("slicing_syntax", Active),
  
 -    ("if_let", Active),
 -    ("while_let", Active),
 +    ("if_let", Accepted),
 +    ("while_let", Accepted),
  
-     // if you change this list without updating src/doc/reference.md, cmr will be sad
- 
      // A temporary feature gate used to enable parser extensions needed
      // to bootstrap fix for #5723.
      ("issue_5723_bootstrap", Accepted),