Clean up the code base in README file

phpcs --standard=Drupal,DrupalPractice --extensions=md string/

FILE: /var/www/html/vb/drupal-2821827/modules/contrib/string/README.md
-------------------------------------------------------------------------
FOUND 1 ERROR AND 14 WARNINGS AFFECTING 14 LINES
-------------------------------------------------------------------------
4 | WARNING | [ ] Line exceeds 80 characters; contains 88 characters
22 | WARNING | [ ] Line exceeds 80 characters; contains 89 characters
24 | WARNING | [ ] Line exceeds 80 characters; contains 112 characters
28 | WARNING | [ ] Line exceeds 80 characters; contains 84 characters
29 | WARNING | [ ] Line exceeds 80 characters; contains 91 characters
32 | WARNING | [ ] Line exceeds 80 characters; contains 91 characters
42 | WARNING | [ ] Line exceeds 80 characters; contains 210 characters
90 | WARNING | [ ] Line exceeds 80 characters; contains 97 characters
98 | WARNING | [ ] Line exceeds 80 characters; contains 94 characters
100 | WARNING | [ ] Line exceeds 80 characters; contains 86 characters
104 | WARNING | [ ] Line exceeds 80 characters; contains 87 characters
108 | WARNING | [ ] Line exceeds 80 characters; contains 87 characters
119 | WARNING | [ ] Line exceeds 80 characters; contains 102 characters
126 | WARNING | [ ] Line exceeds 80 characters; contains 86 characters
126 | ERROR | [x] Expected 1 newline at end of file; 3 found
-------------------------------------------------------------------------
PHPCBF CAN FIX THE 1 MARKED SNIFF VIOLATIONS AUTOMATICALLY
-------------------------------------------------------------------------

Time: 76ms; Memory: 8MB