docs(ascii-art): add details to make audits consistent

Add specification about which shell to use to have consistent
audits for ascii-art main and optional projects.

subjects/ascii-art/audit/README.md

@@ -2,6 +2,8 @@
 
 ###### Has the requirement for the allowed packages been respected? (Reminder for this project: only [standard packages](https://golang.org/pkg/))
 
+###### For consistency, use `bash` as a shell to run the following tests.
+
 ##### Try passing `"hello"` as an argument.
 
 ```
@@ -124,7 +126,7 @@ $
 
 ###### Does it display the right graphical representation in ASCII as above?
 
-##### Try passing `"hello There 1 to 2\!"` as an argument.
+##### Try passing `"hello There 1 to 2!"` as an argument.
 
 ```
  _              _   _                 _______   _                                            _                           _  $
@@ -229,7 +231,7 @@ $
 
 ###### Does it display the right graphical representation in ASCII as above?
 
-##### Try passing `"\\!\" #$%&'()*+,-./"` as an argument.
+##### Try passing `"\!\" #$%&'()*+,-./"` as an argument.
 
 ```
 __       _   _ _           _  _      _    _   __           _    __ __       _                                   __ $

subjects/ascii-art/justify/audit.md

@@ -2,6 +2,8 @@
 
 ###### Has the requirement for the allowed packages been respected? (Reminder for this project: only [standard packages](https://golang.org/pkg/))
 
+###### For consistency, use `bash` as a shell to run the following tests.
+
 ##### Try passing as arguments `--align right something standard`
 
 ```
@@ -40,11 +42,11 @@ Example: go run . --align=right  something  standard
 
 ###### Does it display the correct result at the center?
 
-##### Try passing as arguments `--align=left "23Hello World\!" standard `
+##### Try passing as arguments `--align=left "23Hello World!" standard `
 
 ###### Does it display the correct result at the left side?
 
-##### Try passing as arguments `--align=justify "HELLO there HOW are YOU?\!" thinkertoy`
+##### Try passing as arguments `--align=justify "HELLO there HOW are YOU?!" thinkertoy`
 
 ###### Does it display the correct result justified?
 

subjects/ascii-art/output/audit.md

@@ -2,6 +2,8 @@
 
 ###### Has the requirement for the allowed packages been respected? (Reminder for this project: only [standard packages](https://golang.org/pkg/))
 
+###### For consistency, use `bash` as a shell to run the following tests.
+
 ##### Try passing as arguments `"--output test00.txt banana standard "`
 
 ```