Go to Definition on package name in call to package function opens package name, not function

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. Create the following files, one of which is in a package directory: somepath/+plot/doThing.m
   • somepath/+plot/doThing.m
   • somepath/sample.m
2. In sample.m, make the following call: plot.doThing()
3. Go-to-Definition on doThing - doThing.m opens correctly
4. Go-to-Definition on plot - plot.m opens instead

Expected behavior
In the above example, it is expected that doThing.m will open.

Additional context
Will need to determine how to handle cases like the following: pkg.ClassName.funcName(). If Go-to-Definition is triggered on the class name, do we want to open the class definition? Going to the function definition would often go to the same file, unless it is implemented in a class folder.

_{Internal tracking number: g2885285}

Start by reproducing the issue with somepath/+plot/doThing.m and somepath/sample.m, then trace the Go-to-Definition handling for plot.doThing(). Compare the existing behavior for doThing with the package-name case, and clarify how class-name selections such as pkg.ClassName.funcName() should resolve. Done means selecting plot opens doThing.m consistently with the expected behavior.