Version pragma does not disallow prefixing version ranges with comparison operators

### Description
`pragma solidity` allows version ranges (e.g. `0.8.17-0.8.20`) and using comparison operators before a single version (e.g. `<0.8.17` or `=0.8.20`). Unfortunately it looks like a combination of the two is also allowed, which makes no sense: `<0.8.17 - =0.8.20`.

In version ranges the operator is simply ignored and replaced with `>=` for the first component and `<=` for the second one: https://github.com/ethereum/solidity/blob/ddbef8f65092cd09422366881d0fc1dad5d4b64e/liblangutil/SemVerHandler.cpp#L209-L215

### How to reproduce
This pragma will match `0.8.17`, `0.8.18`, `0.8.19` and `0.8.20`:
```solidity
pragma solidity <0.8.17 - >0.8.20;
```

Read liblangutil/SemVerHandler.cpp around lines 209-215, then reproduce the pragma example from the issue to observe how comparison operators are handled in ranges. Done means a version range prefixed with comparison operators is rejected rather than silently normalized and accepted.

Written by the indexing model from the issue text.