feat(scripts/format): include MDX files by default

Author: jrolfs

src/scripts/__tests__/__snapshots__/format.js.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
-exports[`format --config arg can be used for a custom config 1`] = `prettier --write **/*.+(js|json|less|css|ts|tsx|md) --config ./my-config.js`;
+exports[`format --config arg can be used for a custom config 1`] = `prettier --write **/*.+(js|json|less|css|ts|tsx|md|mdx) --config ./my-config.js`;
 
-exports[`format --ignore-path arg can be used for a custom ignore file 1`] = `prettier --write **/*.+(js|json|less|css|ts|tsx|md) --ignore-path ./.myignore`;
+exports[`format --ignore-path arg can be used for a custom ignore file 1`] = `prettier --write **/*.+(js|json|less|css|ts|tsx|md|mdx) --ignore-path ./.myignore`;
 
-exports[`format --no-write prevents --write argument from being added 1`] = `prettier **/*.+(js|json|less|css|ts|tsx|md) --no-write`;
+exports[`format --no-write prevents --write argument from being added 1`] = `prettier **/*.+(js|json|less|css|ts|tsx|md|mdx) --no-write`;
 
 exports[`format calls prettier CLI with args 1`] = `prettier --write my-src/**/*.js`;

src/scripts/format.js

@@ -33,7 +33,7 @@ const relativeArgs = args.map(a => a.replace(`${process.cwd()}/`, ''))
 
 const filesToApply = parsedArgs._.length
   ? []
-  : ['**/*.+(js|json|less|css|ts|tsx|md)']
+  : ['**/*.+(js|json|less|css|ts|tsx|md|mdx)']
 
 const result = spawn.sync(
   resolveBin('prettier'),