Added autoboxing and its methods

[Yash-Chandrani]

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Description 📜

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context.
Fixes #4035

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Type of change 📝

• Au#dio (Should be in mp3 format Includes speech clarity, Concise ,Low distortion)
• Vi#deo (Animations, screen-recordings, presentations and regular explanatory films are all possibilties etc)
• Documentation (Content Creation in the form of codes or tutorials)
• Other (If you choose other, Please mention changes below)

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Domain of Contribution 📊

• Android Dev #(Flutter)
• Android Dev #(Java)
• Android Dev #(Kotlin)
• Backend Dev #(Java)
• Backend Dev #(.NET)
• Backend Dev #(PHP)
• Backend Dev #(Python)
• C/#CPP
• Competitive #Programming
• Cyber #Security
• DS#A
• Data#base
• Datascience with #Python
• Datascience with #R
• Frontend Dev #HTML/CSS/JS
• Frontend Dev #React/Angular/Vue
• Go#lang
• Interview #Prep
• Java_Domain
• JavaScript_#Domain
• ME#RN
• Machine #Learning
• Open #Source
• Python_#Domain
• Ru#st
• Statis#tics
• UI/#UX

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Checklist ✅

• I follow Contributing Guidelines & Code of conduct of this project.
• I have performed a self-review of my own code or work.
• I have commented my code, particularly in hard-to-understand areas.
• My changes generates no new warnings.
• I'm GWOC'21 contributor

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Screenshots / Gif (Optional) 📸

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