refactor: Enhance docs, add tests in MinHeap

[Hardvan]

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• [x] I have read CONTRIBUTING.md.
• [x] This pull request is all my own work -- I have not plagiarized it.
• [x] All filenames are in PascalCase.
• [x] All functions and variable names follow Java naming conventions.
• [x] All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• [x] All new code is formatted with clang-format -i --style=file path/to/your/file.java

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 80.70175% with 11 lines in your changes missing coverage. Please review.

Project coverage is 71.68%. Comparing base (bc6ea1e) to head (b4c7ffd).

Files with missing lines	Patch %	Lines
...om/thealgorithms/datastructures/heaps/MinHeap.java	80.35%	5 Missing and 6 partials :warning:

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5985      +/-   ##
============================================
+ Coverage     71.37%   71.68%   +0.31%     
- Complexity     4909     4946      +37     
============================================
  Files           650      650              
  Lines         17536    17565      +29     
  Branches       3380     3384       +4     
============================================
+ Hits          12516    12592      +76     
+ Misses         4553     4499      -54     
- Partials        467      474       +7     

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