chore: add VSCode settings and update README.md (markdown-lint) (#209)

* chore: add VSCode settings and update README for clarity**

### CHANGES
- Add recommended extensions for VSCode in `extensions.json`
- Create `settings.json` for custom spell-checker words
- Update README to specify plaintext in code block

* chore: add other technical words to cspell dictionary

---------

Co-authored-by: Brian <bmadcode@gmail.com>

.vscode/extensions.json

@@ -0,0 +1,6 @@
+{
+	"recommendations": [
+		"davidanson.vscode-markdownlint",
+		"streetsidesoftware.code-spell-checker"
+	]
+}