FR allow for multiple capitalizations of a word to be accepted.

**What problem does this solve?**
I have some words that get flagged (in my case, unusual names that I refer to frequently, such as Masako). That works, except it turns out that I would also like to accepts the fully capitalized version of the name (MASAKO). However, accepting one ends up rejecting the other. I would like to have either of these be okay, but things like MAsako be flagged.

**Proposed Solution**
There are many ways it could be done. For example, the dictionary could allow multiple options separated by some character, e.g. a pipe "|".
Masako|MASAKO.

In fact, what I notice now happening, is that if I put both in the user dictionary in the settings, the earlier one gets deleted.

Alternately, in the obsidian popup, if I add one to the dictionary, the other gets flagged.

**Examples**

With MASAKO in the dictionary:

After adding Masako to the dictionary:

**Component**
???
- [ ] Core engine
- [ ] Plugin/Extension
- [ ] Other: _____

**Additional Context**
Any other relevant info.

The issue does not identify a file, test, or component; start by locating user-dictionary handling and capitalization matching in the Rust engine. Reproduce the Masako, MASAKO, and MAsako cases, then verify that the first two are accepted while the mixed-case form remains flagged and that both dictionary entries can coexist.

Written by the indexing model from the issue text.