Fix tokenization for method call on integer

Given the following code snippet:

```
a := 6.add(5)
```

The tokenizer will generate the following tokens:

`Ident(a), Declare(:=), Float(6.), Ident(add), OpenBracket((), Integer(5), CloseBracket())`

However, the `Float(6.)` token should be `Integer(6), Dot(.)`.

This requires either a rewrite of the tokenizer, disallowing `\d+\.` as a float, or tokenizing floats differently.

Start by locating the tokenizer entry point and the logic that recognizes numeric literals. Reproduce tokenization for `a := 6.add(5)` and compare it with the expected Integer(6), Dot(.), Ident(add) sequence. Done means the integer method-call form no longer produces Float(6.) while ordinary float literals still tokenize correctly.

Written by the indexing model from the issue text.