Enable Lint/NoReturnInBeginEndBlocks Cop

[ashmaroli]

• This is a 🐛 bug fix.

Summary

• Enable Lint/NoReturnInBeginEndBlocks
• Split logic in offending Jekyll::PathManager.sanitized_path into a private class method.
• Add a new private cache to stash base_directory appended with a forward slash.

Context

RuboCop 1.2.0 added Lint/NoReturnInBeginEndBlocks. According to its author:

This cop detects the usage of explicit return statements inside a begin..end block in the context of assignments.

The issue is that a return inside a begin..end block in assignment contexts will not assign the desired value to the variable, but will return the value expected to the caller.

In case you're using memoization, the memoized variable will be always nil and the code inside the begin..end block will
execute as many times as you access the memoized variable...

[DirtyF]

🆗 if tests pass

[ashmaroli]

@jekyllbot: merge +bug