Update the introduction

[chrollorifat]

pull request

This commit will:

• Update the introduction with beginner-friendly information
• Fix some minor grammar

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Reviewer Resources:

Track Policies

[jagdish-15]

I think these changes look good. @kahgoh, any thoughts or feedback?

[kahgoh]

I think it might more friendly if we just explain what = does (not sure if the "mathematical equality" will be understood by everyone).

Suggested change

	Updating a variable's value is done through the `=` operator. Here, `=` does not represent mathematical equality. It simply assigns a value to a variable. Once defined, a variable's type can never change.
	The `=` operator assigns a value to a variable. It can also be used to update a variable's value.

[chrollorifat]

But we have to make the distinction between the equals to and assigning operator clear though. I've seen people not really grasping the difference between them when they start out and they usually take it as a equals to sign.