Fixes to the Emscripten and npm article (#8155)
Fixes to the Emscripten and npm article (#8155)

In the *Emscripten and npm* article,

- Added missing commas.
- Removed an extra `;` in a JSON snippet
- Added a missing "the" and a missing "to".
- Changed an uppercase "The" after a colon to a lowercase "the".
- Changed an "an" preceding "`#include`" to an "a".
- Added a missing "that".
- Added a missing closing double quote to argument passed to `echo`.
- Fixed a typo when referring to the `trzeci/emscripten` image.
lucab85/WebFundamentals,google/WebFundamentals,myakura/WebFundamentals,lucab85/WebFundamentals,myakura/WebFundamentals,google/WebFundamentals,lucab85/WebFundamentals,google/WebFundamentals,google/WebFundamentals,myakura/WebFundamentals,lucab85/WebFundamentals,myakura/WebFundamentals