[Feature request] git config - includeif - resolve symlinks using realpath

Hello

It will be useful if the path in includeIf "gitdir" uses the resolved path.

For example, in the following snippet, ~/Documents/Git/Wiki is symlinked to several different locations. When using git from other locations, the following won't get included. I verified this using `git config --list --show-origin --show-scope`

```
[includeIf "gitdir:~/Documents/Git/Wiki/"]
	path = ~/Documents/Git/Wiki/.gitconfig
```

Feature request: Please resolve the path, before using it.