Fix typo in regular expression string

[jahvi]

It should say "regular expressions" instead of "regular exceptions".

[keharper]

Chuckling at this typo. Thanks for fixing it.

[hostep]

@jahvi, @keharper: this fix is incorrect.

The line which needs to be changed is:
In the Search String box specify the user-agent using either normal strings or regular exceptions (PCRE).

The line which is now changed was originally correct.

@jahvi: can you create a new PR which fixes this? Thanks!

[jahvi]

@hostep My bad, I'll create a new PR with the correct fix.