julia-mode.el: improve matching of function assignment syntax

The case when a module qualification is prepended to the function name
is handled like in normal function syntax, and support for one level of
nested parentheses is added, e.g. M.f(x::(Int,)) = 1 (tuple types) or
M.f(x, y=length(x)).

contrib/julia-mode.el

@@ -148,11 +148,15 @@ This function provides equivalent functionality, but makes no efforts to optimis
 
 (defconst julia-function-assignment-regex
  (rx line-start symbol-start
+ (* (seq (1+ (or word (syntax symbol))) ".")) ; module name
  (group (1+ (or word (syntax symbol))))
  (* space)
  (? "{" (* (not (any "}"))) "}")
  (* space)
- "(" (* (not (any ")"))) ")"
+ "(" (* (or
+ (seq "(" (* (not (any "(" ")"))) ")")
+ (not (any "(" ")"))))
+ ")"
  (* space)
  "="))