Add inline regex support to match capital letters and lowercase letters explicitly

[SebastianMC]

Discussed in https://github.com/SebastianMC/obsidian-custom-sort/discussions/114

^{Originally posted by **catvatar** November 21, 2023} ## I use capital letters to distinguish between self contained notes and aggregating notes So I would like notes starting with capital letters to be sorted first. ### Example - note A - Note A - note B - Note B Sorted: - Note A - Note B - note A - note B For now I don't see a clear way of doing this. My `sortspec.md` file looks like this ``` --- sorting-spec: |- target-folder: /* /folders < a-z /:files < a-z README sortspec --- ```

[SebastianMC]

Added in release 2.1.1