[Concept Entry] C++ Count Function map

[codecademy-docs]

Reason/inspiration (optional)

We would like a new entry on the count() term under C++ Maps. The entry should go in a new file under docs/content/cpp/concepts/maps/terms/count/count.md.

The entry should include:

• An introduction to the concept
• A Syntax section that provides the syntax for the concept
• An Example section that provides an example demonstrating the concept in use
• A Codebyte Example section that provides a codebyte example demonstrating the concept in use

Please refer to the term entry template, content standards and markdown style guide when working on the PR for this issue.

Entry Type (select all that apply)

New Concept Entrty for Existing Topic

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