Update 02-hello-world.mdx

[ObjectPlayer]

I have updated the grammatical mistakes in 02-hello-world.mdx file

[joshuahannan]

Thank you so much for finding all of these! Great work. 👍

[turbolent]

Thank you!

[codecov-commenter]

Codecov Report

Merging #1365 (0dd839a) into master (3c24a0e) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1365   +/-   ##
=======================================
  Coverage   75.95%   75.95%           
=======================================
  Files         279      279           
  Lines       38717    38717           
=======================================
  Hits        29406    29406           
  Misses       7968     7968           
  Partials     1343     1343           

Flag	Coverage Δ
unittests	75.95% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3c24a0e...0dd839a. Read the comment docs.