Determine behavior on equal titles

[kmaasrud]

Equal titles are allowed, as the IDs serve as the one truth to what note is which. However, ID lookup and internal link creation can be ambiguous when notes share an equal title. We need to determine how mdzk should handle this.

Currently, looking up an ambiguous title returns the last note walked. The walk happens randomly, so this behavior is not consistent, though it might be the best we can get without sacrificing performance. Giving the user a warning would likely be the most sensible solution.