rename std::vec_ng -> std::vec

Closes #12771

src/libsyntax/ext/tt/macro_parser.rs

@@ -22,7 +22,7 @@ use parse::token::{Token, EOF, Nonterminal};
 use parse::token;
 
 use collections::HashMap;
-use std::vec_ng::Vec;
+use std::vec::Vec;
 
 /* This is an Earley-like parser, without support for in-grammar nonterminals,
 only by calling out to the main rust parser for named nonterminals (which it

src/libsyntax/ext/tt/macro_rules.rs

@@ -28,7 +28,7 @@ use print;
 use util::small_vector::SmallVector;
 
 use std::cell::RefCell;
-use std::vec_ng::Vec;
+use std::vec::Vec;
 
 struct ParserAnyMacro<'a> {
     parser: RefCell<Parser<'a>>,

src/libsyntax/ext/tt/transcribe.rs

@@ -18,7 +18,7 @@ use parse::token;
 use parse::lexer::TokenAndSpan;
 
 use std::cell::{Cell, RefCell};
-use std::vec_ng::Vec;
+use std::vec::Vec;
 use collections::HashMap;
 
 ///an unzipping of `TokenTree`s