Avoid creating new strings when parsing PcData

[3bdNKocY]

Avoid string concat and substring operations to optimize memory usage.
This reduces memory usages by around 80MB on a local large html file.

[JonathanMagnan]

Hello @3bdNKocY ,

Thank you for your pull. we will make a slight change to it, but besides it, everything looks great.

Best Regards,

Jon

[JonathanMagnan]

Here is the small improvement we made with your modification: 43d5133

There is no point in starting the string.Compare logic if the tagStartMatching already return false.

I'm not sure how much it will improve the performance but it should certainly doesn't hurt it ;)

Best Regards,

Jon