auto merge of #18789 : cuviper/rust/vim-move, r=alexcrichton

It used to be in `rustKeyword`, but commit 5c75f21 removed it.  It was reintroduced as a keyword in 0.12.0 to indicate by-value closures, and I think `rustStorage` highlighting makes sense for that purpose.

Author: bors

src/etc/vim/syntax/rust.vim

@@ -30,7 +30,7 @@ syn keyword   rustKeyword     unsafe virtual where while
 syn keyword   rustKeyword     use nextgroup=rustModPath skipwhite skipempty
 " FIXME: Scoped impl's name is also fallen in this category
 syn keyword   rustKeyword     mod trait struct enum type nextgroup=rustIdentifier skipwhite skipempty
-syn keyword   rustStorage     mut ref static const
+syn keyword   rustStorage     move mut ref static const
 
 syn keyword   rustInvalidBareKeyword crate