allowRegexes is not working properly

Hi @asweigart, Hi @all,

I recently found a bug (or at least a documentation gap) in this module.
For test purposes, I wrote an input validation where the user has to type in a password with a specific pattern (allowed symbols and minimal/maximal length). If I only use the `allowRegex` parameter it isn't working properly:
code:
```python
password = pyip.inputStr(prompt='Type in your password: ', allowRegexes=[r"[A-Za-z0-9-_]{6,18}"], blockRegexes=[r"."])
```
log:
```bash
Type in your password: $hort
```
It's only working, if the `blockRegex` is set too:
code:
```
password = pyip.inputStr(prompt='Type in your password: ', allowRegexes=[r"[A-Za-z0-9-_]{6,18}"], blockRegexes=[r"."])
```
log:
```
Type in your password: $short
This response is invalid.
```

Maybe the code has to be updated or the documentation has to be changed.

Thanks.

Kind Severin

Start by reproducing the two inputStr examples from the issue and then trace the allowRegexes and blockRegexes handling in the input validation implementation. Done means the documented password pattern behaves consistently when allowRegexes is used alone, or the documentation clearly explains the required configuration.

Written by the indexing model from the issue text.