Fixes #46

Parentheses in URI

• ( and ) in a URI should be paired, otherwise they are removed from the match. This fixes the markdown link problem like [link](https://example.com) --- which is previously matched as https://example.com) but now it's correctly matched as https://example.com.
• On the other hand, matched parentheses in a URI can be detected, like https://en.wikipedia.org/wiki/WWW_(disambiguation).
• NOTE: This regex cannot detect nested parentheses. IMO it's acceptable for daily normal usecases.

Trailing periods/commas in URI

• In a sentence like Refer to the doc: https://doc.example.com/index.html., the regex detect the URI as https://doc.example.com/index.html. with the trailing period, leading us to the 404 page.
• I couldn't find a sophisticated way to detect/remove such trailing periods (note: lookaround is not what we want here) thus I wrote a small snippet to remove periods and commas in C code.