Fix removing parentheses when using deducing assignement

The issue is caused by `emit(expression_list_node)` that skips parentheses
when node is inside initializer - that serves cases like:
```cpp
v : std::vector<int> = (1,2,3);
```
Where it generates:
```cpp
std::vector<int> v{1,2,3};
```

When `:=` is used in the following cases:
```cpp
d := (1 + 2) * (3 + 4) * (5 + 6);
```
It removes first parentheses and we end up with:
```cpp
auto d = {1 + 2 * (3 + 4) * ( 5 + 6)};
```

This change corrects this behaviour on the parsing side it checks if it
is initializer with a explicit type or is the type deduced
(it is done by checking if before `Assignement` there is a `Colon`).

```cpp
            bool inside_initializer = (
                peek(-1) && peek(-1)->type() == lexeme::Assignment
                && peek(-2) && peek(-2)->type() != lexeme::Colon
            );
```

Author: filipsajdak

source/parse.h

@@ -2724,7 +2724,10 @@ class parser
             //      || curr().type() == lexeme::LeftBrace
             )
         {
-            bool inside_initializer = (peek(-1)->type() == lexeme::Assignment);
+            bool inside_initializer = ( 
+                peek(-1) && peek(-1)->type() == lexeme::Assignment
+                && peek(-2) && peek(-2)->type() != lexeme::Colon
+            );
             auto open_paren = &curr();
             auto close = close_paren_type(open_paren->type());
             auto close_text = [&] () -> std::string { if (close == lexeme::RightParen) { return ")"; } return "}"; }();