Properly detect whether a C file is using tabs or spaces for Vim.

Closes issue #5611. Thanks Kirk McDonald and Johannes Hoff.
diff --git a/Misc/NEWS b/Misc/NEWS
index 011d320..1507ebe 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -1607,6 +1607,11 @@
 
 - Issue #2389: Array objects are now pickled in a portable manner.
 
+Misc
+----
+
+- Issue #5611: Auto-detect whether a C file uses tabs or spaces in Vim.
+
 
 What's New in Python 2.6 final
 ==============================