No docs about supported regular expression syntax

[EmilyGraceSeville7cf]

There is no way to understand which regex features are supported without testing it manually. Please specify it in README as basic regex|extended regex|perl compatible regex (maybe another regex flavor used).

You can assign me to this issue and I will try to fix it.

[aum7]

give an example of regex use in search & replace case

[dansmindspace]

Here are somethings I worked out about how it supports RegEx capture groups:

1. They don't support (?<name> pattern)
2. Captured groups indexes start at 1
3. Use \i to reference a capture group in the replace field i is the index to use not a literal i

Example:

File name: Test 123

Find: (.*) (\d\d\d)
Replace: \2 \1
Result: 123 Test