Function Score weight returns the wrong reference

[tatarco]

by the documentation a function score can contain only weight and no other inner functions
in the java api in order to build the FunctionScore we must "hold" a "ContainerBuilder" object, that is only provided as
a response to exp, gauss etc, the weight method (FunctionScore.java:306) returns builder instead of returning ContainerBuilder making this use case impossible to invoke within the java Api

[anton-filatov]

I faced with the same problem. Api specification at compound.ts also states that "This container is valid without a variant. Also, despite being documented as a function, 'weight' is actually a container property that can be combined with a function".

[swallez]

This has been fixed in PR #257