chore: vendor MDX deps for Jest and the MDX 2 upgrade (facebook#8515)

Author: slorber

.cspell.json

@@ -31,7 +31,8 @@
     "*.xyz",
     "*.docx",
     "versioned_docs",
-    "*.min.*"
+    "*.min.*",
+    "jest/vendor"
   ],
   "ignoreRegExpList": ["Email", "Urls", "#[\\w-]*"]
 }

.eslintignore

@@ -8,6 +8,7 @@ build
 coverage
 jest.config.js
 jest.transform.js
+jest/vendor
 examples/
 
 packages/lqip-loader/lib/

.prettierignore

@@ -4,6 +4,9 @@ node_modules
 build
 coverage
 .docusaurus
+
+jest/vendor
+
 packages/lqip-loader/lib/
 packages/docusaurus/lib/
 packages/docusaurus-*/lib/*