Update runtime files.
diff --git a/runtime/syntax/bib.vim b/runtime/syntax/bib.vim
index 3743fb0..f84d5ca 100644
--- a/runtime/syntax/bib.vim
+++ b/runtime/syntax/bib.vim
@@ -2,7 +2,7 @@
" Language: BibTeX (bibliographic database format for (La)TeX)
" Maintainer: Bernd Feige <Bernd.Feige@gmx.net>
" Filenames: *.bib
-" Last Change: 2011 Dec 25
+" Last Change: 2014 Mar 26
" Thanks to those who pointed out problems with this file or supplied fixes!
@@ -28,7 +28,7 @@
syn keyword bibType contained incollection inproceedings manual
syn keyword bibType contained mastersthesis misc phdthesis
syn keyword bibType contained proceedings techreport unpublished
-syn keyword bibType contained string
+syn keyword bibType contained string preamble
syn keyword bibEntryKw contained address annote author booktitle chapter
syn keyword bibEntryKw contained crossref edition editor howpublished