Missing spaces in PragmaDirective

Contracts such as the [Ballot contract](https://remix.ethereum.org/?#language=solidity&version=0.8.10&code=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) shown in the official documentation use pragma versions that follow the [same syntax as npm](https://docs.npmjs.com/cli/v6/using-npm/semver):

```
pragma solidity >=0.7.0 <0.9.0;
```

[According to the official documentation](https://docs.soliditylang.org/en/develop/layout-of-source-files.html), this is allowed and the parser seems to support this. However, when parsing contracts like this, the value associated with the `PragmaDirective` doesn't have any spaces:

```
>>> sourceUnit['children'][0]
{'type': 'PragmaDirective', 'name': 'solidity', 'value': '>=0.7.0<0.9.0'}
```

Is there any reason for omitting the spaces? Unfortunately, this precludes the use of other modules that already parse version strings that follow the npm specification. This suggests that it would be better to keep the original format.