chore: rename deep_clone into copy

[GMH233]

#1461
Basically, just change

pub fn deep_clone[V](self : T[V]) -> T[V] {
  *some code*
}

To

/// @alert deprecated "Use `copy` instead"
/// @coverage.skip
pub fn deep_clone[V](self : T[V]) -> T[V] {
  copy(self)
}
pub fn copy[V](self : T[V]) -> T[V] {
  *some code*
}

[peter-jerry-ye-code-review]

‼️ This code review is generated by a bot. Please verify the content before trusting it.

From the git diff provided, I can identify the following potential issues:

1. Inconsistent Function Naming: The codebase is transitioning from deep_clone to copy, but there might be other parts of the codebase still using deep_clone. This could lead to confusion and maintainability issues. While the deprecated annotation is added, existing code might still be using the old function name.

2. Shallow Copy Behavior: The copy function (previously deep_clone) is explicitly noted to only copy the tree structure and not the values. This could be problematic if users expect a true deep copy of the data structure. The comment states "It requires a Clone trait on T, which we don't have yet" - this limitation should be addressed in future updates.

3. Multiple Ways to Calculate Difference: The code shows both diff and difference methods, with diff being marked as deprecated. Having two methods for the same operation could lead to confusion and inconsistency in code using this library. The deprecated method should eventually be removed to avoid confusion.

These observations suggest a transition period in the codebase where older patterns are being updated to newer ones, which could temporarily impact code clarity and consistency.

[coveralls]

Pull Request Test Coverage Report for Build 5014

Details

• 3 of 3 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 85.007%

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Totals
Change from base Build 5011:	0.0%
Covered Lines:	5222
Relevant Lines:	6143

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💛 - Coveralls