* fixing #24573
fixing #24573 - Guide: Let and Const - Unwanted underscores in search result and incorrect URL
- changed underscore to hyphen, same problem was also happening with arrow_functions
https://github.com/freeCodeCamp/freeCodeCamp/issues/24573
* fix: added 3 backticks for code sections
* Make nouns plural in keeping with 'world objects'
Sentence subject 'real world objects' is plural, so noun derivatives should be plural as well.
* Grammar and readability edits.