Regex: special case `^` and `$` require special treatment

[lifenjoiner]

a8471540

1. Continuous search after found, requires one extra move;
2. Select All does not work yet.

[zufuliu]

^ and $ seems is working, what's the test case?

[lifenjoiner]

Yes, your example works, and the special cases are:

1. only ^ or $, to quickly select the beginning or ending of lines, especially the ending;
2. ^ and $, to select empty lines.

"Find All" works, other actions don't.

[zufuliu]

empty matches are skipped: https://github.com/zufuliu/notepad4/blob/10605475bd597620f0d124a747f36702524e03fa/src/Edit.cpp#L5480-L5489

https://github.com/zufuliu/notepad4/blob/10605475bd597620f0d124a747f36702524e03fa/src/Edit.cpp#L5590-L5595