Fix issues reported by verification scripts

[yuanchen8911]

This PR addresses the following issues reported by verification scripts (spelling, gofmt, and golint) in the current code and documentation:

1. Go import package order, e.g., knavigator packages should be at the end.
2. Typos.

[dmitsh]

In Golang, it is customary to organize import statements into groups:

Standard library packages
Third-party packages
Internal packages of the current project

[yuanchen8911]

In Golang, it is customary to organize import statements into groups:

Standard library packages Third-party packages Internal packages of the current project

That's my understanding too. Those changes were automatically generated by the script. It's stragne. I've reverted all the changes except the format one.