maint/dev ~ (VSCode) add cspell spell-checker extension to recommendations

.vscode/extensions.json

@@ -1,10 +1,12 @@
 {
-  // See http://go.microsoft.com/fwlink/?LinkId=827846
-  // for the documentation about the extensions.json format
+  // spell-checker:ignore (misc) matklad
+  // see <http://go.microsoft.com/fwlink/?LinkId=827846> for the documentation about the extensions.json format
   "recommendations": [
     // Rust language support.
     "rust-lang.rust",
     // Provides support for rust-analyzer: novel LSP server for the Rust programming language.
-    "matklad.rust-analyzer"
+    "matklad.rust-analyzer",
+    // `cspell` spell-checker support
+    "streetsidesoftware.code-spell-checker"
   ]
 }