Improved documentation & types

[ghost]

1. Improved documentation for lib/node.d.ts, lib/comment.d.ts and lib/declaration.d.ts
2. Changed return type for Node.clone() from this to Node, reason: this is the reference to the original node, and having type of original node instance on a duplicated node instance is not correct method. click here to view

[ghost]

I have pushed the changes, they appear on my fork but not appearing here... @ai

[ai]

Suggested change

[ai]

Need to remove name duplication here as well

[ai]

I have pushed the changes, they appear on my fork but not appearing here... @ai

Strange.

What we can try to fix the problem:

1. Close this PR and open another from your branch (but GitHub will not suggest you a branch in yellow banner, you will need to click New PR and manually select branch). If not, I will get changes manually from your branch, don't worry (just don't delete branch in your repo).
2. Avoid do merge main commits. They are not very stable.
3. After your PR was accepted, I prefer to delete my fork (copy of PostCSS repo in your account) and create a fork again for the next PR.

[idoros]

Changed return type for Node.clone() from this to Node, reason: this is the reference to the original node, and having type of original node instance on a duplicated node instance is not correct method

@vikaskaliramna07 - can you expand on the reasoning behind this? When an instance of postcss.Root is cloned, the returned copy is also a Root node. This new return type require casting back into the original type. How can clone change the type of the returned instance?

Also you changed the jsdoc on the clone function to:

• The clone method creates clone of an existing node,
• which includes all the properties and their values, that
• includes raws but not type.

From what I can see in the code, there is no specific handling of type field, the clone simply creates a new instance from the prototype and then copy self owned properties from the original to the clone. This clone method is inherited to other types of nodes and causes a regression in code that uses it.