patch 8.1.2127: the indent.c file is a bit big

Problem:    The indent.c file is a bit big.
Solution:   Move C-indent code a a new cindent.c file.  Move other
            indent-related code to indent.c. (Yegappan Lakshmanan,
            closes #5031)
diff --git a/src/userfunc.c b/src/userfunc.c
index a6ac29e..a775212 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -8,7 +8,7 @@
  */
 
 /*
- * eval.c: User defined function support
+ * userfunc.c: User defined function support
  */
 
 #include "vim.h"