Use minlines 600 to prevent syntax highlight sync problems

Author: amiralies

syntax/rescript.vim

@@ -2,7 +2,8 @@ if exists("b:current_syntax")
   finish
 endif
 
-syntax sync fromstart
+" See https://github.com/rescript-lang/vim-rescript/issues/14
+syntax sync minlines=600
 
 " Boolean
 syntax keyword resBoolean true false