Update the module info files.

xmlsitemap.info.yml

 name: XML sitemap
 type: module
-description: Creates an XML sitemap conforming to the <a href="http://sitemaps.org/">sitemaps.org protocol</a>.
-package: XML sitemap
+description: 'Creates an XML sitemap conforming to the <a href="http://sitemaps.org/">sitemaps.org protocol</a>.'
+package: 'XML sitemap'
 core: 8.x
 configure: xmlsitemap.admin_search
 recommends: robotstxt

xmlsitemap_engines/xmlsitemap_engines.info.yml

 name: XML sitemap engines
 type: module
-description: Submit the sitemap to search engines.
-package: XML sitemap
+description: 'Submit the sitemap to search engines.'
+package: 'XML sitemap'
 core: 8.x
 configure: xmlsitemap_engines.settings
 dependencies:
     - xmlsitemap
-