docs(master-the-ls): fix readme and change to script instead of a file

sh/tests/master-the-ls_test.sh

@@ -8,8 +8,8 @@ IFS='
 script_dirS=$(cd -P "$(dirname "$BASH_SOURCE")" &>/dev/null && pwd)
 
 challenge() {
-    submitted=$(cd "$1" && bash "$script_dirS"/student/master-the-ls)
+    submitted=$(cd "$1" && bash "$script_dirS"/student/master-the-ls.sh)
-    expected=$(cd "$1" && bash "$script_dirS"/solutions/master-the-ls)
+    expected=$(cd "$1" && bash "$script_dirS"/solutions/master-the-ls.sh)
 
     diff <(echo "$submitted") <(echo "$expected")
 }

subjects/devops/master-the-ls/README.md

@@ -2,7 +2,7 @@
 
 ### Instructions
 
-Put in a file `master-the-ls`, the command line that will:
+Create a script `master-the-ls`, that will do the following:
 
 - list the files and directories of the current directory.
 - Ignore the hidden files, the "." and the "..".