rust.vim: Links previously unused rustFuncCall

This allows for highlighting of function calls
for free floating, member, and static functions.

Author: Jeaye

src/etc/vim/syntax/rust.vim

@@ -143,6 +143,7 @@ hi def link rustConditional   Conditional
 hi def link rustIdentifier    Identifier
 hi def link rustModPath       Include
 hi def link rustFuncName      Function
+hi def link rustFuncCall      Function
 hi def link rustCommentDoc    SpecialComment
 hi def link rustComment       Comment
 hi def link rustMacro         Macro