* moved unit tests to conditional compile
made module `tests` and conditionally compiled
* added test to check for duplicate keys in builtin
checks all pairs in GlobMatcher::mappings via `GlobMatcher::glob`s `Eq`
panics at first match
```rs
SyntaxMapping {
mappings: Vec<(
GlobMatcher {
glob: Glob, ...,
}, ...,
}, ...,
}
```
* output more info with test failure
* dont duplicatively add git config path
* use guard in match for adding builtin git config syntax mapping
---------
Co-authored-by: Orion Yeung <11580988+orionyeung001@users.noreply.github.com>
