Correct description in messages; add 'tel' input type

go-back-with-backspace/build-zip.sh

 #!/bin/bash
 # Zip the files needed for this extension, excluding screenshots, promotional
 # images, and backup files.
 
 # Constants
 readonly ZIP_FILE='go-back-with-backspace.zip'
 # The individual icon files are listed so an error will be raised if one is
 # missing.
 declare -ar ZIP_CONTENTS=(_locales/
                           icons/
                           icons/icon16.png
                           icons/icon32.png
                           icons/icon48.png
                           icons/icon128.png
                           content_script.js
                           is_editable.js
                           manifest.json
                           readme.txt)
 
 # Remove backup files.
 rm -f $(find . -name \*~ -or -name \#\*\#)
 
-if ! mkdir icons; then
+if ! mkdir -p icons; then
   echo "Error creating icons/ directory" >&2
   exit 1
 fi
 
 if ! cp assets/icon*.png icons/; then
   echo "No icon images found in icons/" >&2
   exit 2
 fi
 
 rm -f "${ZIP_FILE}"
 if ! zip -r --quiet --must-match "${ZIP_FILE}" "${ZIP_CONTENTS[@]}"; then
   echo "Error zipping required files (${ZIP_CONTENTS[@]})" >&2
   exit 3
 fi