Allow us to specify tag and search pattern in a similar way cmp allows us

### 🚀 The feature, motivation and pitch

At the moment, non-ASCII tags do not work properly, unlike how it works in Obsidian. HIghlighting, autocompletion and search do not work for tags like `#життя`.
cmp has a similar problem, but allows us to configure patterns that covers desired set of unicode characters.

### Alternatives

Alternatively, the default pattern may cover all unicode letters, or there could be an option for enabling this behavior.

### Additional context

_No response_

Start by tracing how tag patterns are handled for highlighting, autocompletion, and search, then compare the configurable pattern behavior described for cmp. Done means tags such as #життя work consistently in all three areas, either through configurable Unicode patterns or a default pattern that covers them.

Written by the indexing model from the issue text.