docs: fix spelling and grammar (#13862)

Fixed various spelling errors and grammatical issues across multiple .mdx documentation files.

www/apps/resources/app/admin-components/components/header/page.mdx

@@ -128,7 +128,7 @@ It accepts the following props:
           name: "props",
           type: "object",
           optional: false,
-          description: `This property is only accepted if \`type\` is \`button\` or \`action-menu\`. If \`type\` is \`button\`, it accepts the [props to pass to the UI Button component](https://docs.medusajs.com/components/button). If \`type\` is \`action-menu\`, it accepts the props to pass to the action menu, explaind in [this guide](../action-menu/page.mdx).`,
+          description: `This property is only accepted if \`type\` is \`button\` or \`action-menu\`. If \`type\` is \`button\`, it accepts the [props to pass to the UI Button component](https://docs.medusajs.com/components/button). If \`type\` is \`action-menu\`, it accepts the props to pass to the action menu, explained in [this guide](../action-menu/page.mdx).`,
         },
         {
           name: "link",