Documentation for each function/type/const must be placed right before the declaration:

Sometimes one line isn’t enough to explain what a function does, in that case comments should span to the documented function using single line comments:

// if `dupes` is false all duplicate values are eliminated in the process.
    // ...
}

An overview of the module must be placed in the first comment right after the module’s name.

Comments spanning multiple lines are merged together using spaces, unless

• the line is empty
• the line is purely of at least 3 of -, =, _, , ~ (horizontal rule)
• the line starts with at least one # followed by a space (header)
• the line starts and ends with a | (table)