feat: semantics for if statements and multi-prong if statements

src/Ast.zig

@@ -22,10 +22,11 @@ pub const Node = struct {
 
     pub const Tag = enum {
         file,
-        false_literal,
         true_literal,
+        false_literal,
         number_literal,
         string_literal,
+        string_expr,
         empty_string,
         identifier,
         add_expr,
@@ -73,7 +74,6 @@ pub const Node = struct {
         temp_decl,
         parameter_decl,
         ref_parameter_decl,
-        string_expr,
         argument_list,
         parameter_list,
         switch_stmt,