Enhance missing argument validation

[volsa]

Currently we have two different error messages for missing arguments, either a

• "Argument <name> is missing" or a
• "this POU takes 1 argument but 0 arguments were supplied"

A better approach would be to merge both these validations into one, displaying something along "Argument(s) are missing"

---

FUNCTION_BLOCK foo
VAR_INPUT 
    x : DINT := 34;
END_VAR
METHOD bar 
VAR_INPUT 
    x : DINT := 34;
END_VAR
END_METHOD
END_FUNCTION_BLOCK 

FUNCTION baz
VAR_INPUT 
    x : DINT := 34;
END_VAR
END_FUNCTION

FUNCTION main : DINT 
VAR 
    fb: foo;
END_VAR
    fb.bar();
    baz();
END_FUNCTION

Both the calls to fb.bar and baz have the same error, yet yield different diagnostics:

error[E030]: Argument `x` is missing
   ┌─ target/demo.st:22:5
   │
22 │     fb.bar();
   │     ^^^^^^ Argument `x` is missing

error[E032]: this POU takes 1 argument but 0 arguments were supplied
   ┌─ target/demo.st:23:5
   │
23 │     baz();
   │     ^^^ this POU takes 1 argument but 0 arguments were supplied

Compilation aborted due to critical errors.

Originally posted by @mhasel in https://github.com/PLC-lang/rusty/issues/1364#issuecomment-2488507797