Make test commands work well with copy to clipboard action

Author: zachborboa

TESTING.md

@@ -4,20 +4,26 @@
 
 To run tests:
 
-    $ git clone https://github.com/php-curl-class/php-curl-class.git
-    $ cd php-curl-class/
-    $ composer update
-    $ ./tests/run.sh
+```bash
+git clone https://github.com/php-curl-class/php-curl-class.git
+cd php-curl-class/
+composer update
+./tests/run.sh
+```
 
 To run select tests:
 
-    $ git clone https://github.com/php-curl-class/php-curl-class.git
-    $ cd php-curl-class/
-    $ composer update
-    $ ./tests/run.sh --filter=keyword
+```bash
+git clone https://github.com/php-curl-class/php-curl-class.git
+cd php-curl-class/
+composer update
+./tests/run.sh --filter=keyword
+```
 
 To test all PHP versions in containers:
 
-    $ git clone https://github.com/php-curl-class/php-curl-class.git
-    $ cd php-curl-class/
-    $ ./tests/test_all.sh
+```bash
+git clone https://github.com/php-curl-class/php-curl-class.git
+cd php-curl-class/
+./tests/test_all.sh
+```