add init and deinit snippets for zig

lua/snippets/zig.lua

@@ -7,4 +7,18 @@ return {
     f(file_name, {}),
     t(" = @This();"),
   }),
+
+  s("init", {
+    t("pub fn init() !*"),
+    f(file_name, {}),
+    t({ " {", "\tconst self = try gpa.create(" }),
+    f(file_name, {}),
+    t({ ");", "\tself.* = .{};", "\treturn self;", "}" }),
+  }),
+
+  s("deinit", {
+    t("pub fn deinit(self: *"),
+    f(file_name, {}),
+    t({ ") void {", "\tgpa.destroy(self);", "}" }),
+  }),
 }