checker: make the misssing shared/mut modifer in fn and method calls error clearer

vlib/v/checker/fn.v

@@ -812,8 +812,8 @@ pub fn (mut c Checker) fn_call(mut node ast.CallExpr, mut continue_check &bool)
 		} else {
 			if param.is_mut {
 				tok := call_arg.share.str()
-				c.error('`$node.name` parameter `$param.name` is `$tok`, you need to provide `$tok` e.g. `$tok arg${
+				c.error('function `$node.name` parameter `$param.name` is `$tok`, so use `$tok $call_arg.expr` instead',
-					i + 1}`', call_arg.expr.pos())
+					call_arg.expr.pos())
 			} else {
 				c.fail_if_unreadable(call_arg.expr, typ, 'argument')
 			}
@@ -1307,8 +1307,8 @@ pub fn (mut c Checker) method_call(mut node ast.CallExpr) ast.Type {
 			} else {
 				if param_is_mut {
 					tok := arg.share.str()
-					c.error('`$node.name` parameter `$param.name` is `$tok`, you need to provide `$tok` e.g. `$tok arg${
+					c.error('method `$node.name` parameter `$param.name` is `$tok`, so use `$tok $arg.expr` instead',
-						i + 1}`', arg.expr.pos())
+						arg.expr.pos())
 				} else {
 					c.fail_if_unreadable(arg.expr, got_arg_typ, 'argument')
 				}

vlib/v/checker/tests/chan_args.out

@@ -12,7 +12,7 @@ vlib/v/checker/tests/chan_args.vv:5:19: error: cannot use `float literal` as `&f
       |                      ~~~
     6 |     b := 2.5
     7 |     _ := ch.try_pop(b)
-vlib/v/checker/tests/chan_args.vv:7:18: error: `try_pop` parameter `obj` is `mut`, you need to provide `mut` e.g. `mut arg1`
+vlib/v/checker/tests/chan_args.vv:7:18: error: method `try_pop` parameter `obj` is `mut`, so use `mut b` instead
     5 |     _ := ch.try_push(2.5)
     6 |     b := 2.5
     7 |     _ := ch.try_pop(b)

vlib/v/checker/tests/mut_arg.out

@@ -1,25 +1,25 @@
-vlib/v/checker/tests/mut_arg.vv:6:3: error: `f` parameter `par` is `mut`, you need to provide `mut` e.g. `mut arg1`
+vlib/v/checker/tests/mut_arg.vv:6:3: error: function `f` parameter `par` is `mut`, so use `mut [3, 4]` instead
     4 | }
-    5 |
+    5 | 
     6 | f([3,4])
       |   ~~~~~
     7 | mut a := [1,2]
     8 | f(a)
-vlib/v/checker/tests/mut_arg.vv:8:3: error: `f` parameter `par` is `mut`, you need to provide `mut` e.g. `mut arg1`
+vlib/v/checker/tests/mut_arg.vv:8:3: error: function `f` parameter `par` is `mut`, so use `mut a` instead
     6 | f([3,4])
     7 | mut a := [1,2]
     8 | f(a)
       |   ^
-    9 |
+    9 | 
    10 | g(mut [3,4])
 vlib/v/checker/tests/mut_arg.vv:10:7: error: array literal can not be modified
     8 | f(a)
-    9 |
+    9 | 
    10 | g(mut [3,4])
       |       ~~~~~
    11 | g(mut a)
 vlib/v/checker/tests/mut_arg.vv:11:7: error: `g` parameter `par` is not `mut`, `mut` is not needed`
-    9 |
+    9 | 
    10 | g(mut [3,4])
    11 | g(mut a)
       |       ^

vlib/v/checker/tests/mut_interface_param_err.out

@@ -1,4 +1,4 @@
-vlib/v/checker/tests/mut_interface_param_err.vv:19:10: error: `add` parameter `widget` is `mut`, you need to provide `mut` e.g. `mut arg1`
+vlib/v/checker/tests/mut_interface_param_err.vv:19:10: error: method `add` parameter `widget` is `mut`, so use `mut btn` instead
    17 |     mut win := Window{}
    18 |     mut btn := Button{}
    19 |     win.add(btn)  // should be an error here