style: Enable vscode spellcheck and fix typos/style (#2888)

Signed-off-by: fria <[email protected]>
Signed-off-by: Daniel Gray <[email protected]>

Author: jonaharagon

.markdownlint.yml

@@ -27,5 +27,6 @@ code-block-style: false
 no-hard-tabs: true
 emphasis-style:
   style: "asterisk"
-no-duplicate-header: false
 no-trailing-punctuation: false
+no-duplicate-heading:
+  siblings_only: true