Note SQLi as an abbreviation for SQL injection

People may see this abbreviation in the literature,
so we should mention it.

Signed-off-by: David A. Wheeler <[email protected]>

Author: david-a-wheeler

secure_software_development_fundamentals.md

@@ -2357,7 +2357,7 @@ This is false. Clearly, if you pick known *insecure* software, you will have a p
 
 **Exploits of a Mom**, retrieved from [xkcd.com](https://xkcd.com/327/), licensed under [CC-BY-NC-2.5](https://creativecommons.org/licenses/by-nc/2.5/)
 
-Most database systems include a language that can let you create arbitrary queries, and typically many other functions too (e.g., creating and modifying things). The SQL language is especially common, and while some database systems use other languages, those other languages often have similarities with SQL. Such languages, including SQL, include metacharacters. When attackers can insert metacharacters into a SQL command to cause a security problem, the attack is called an *SQL injection attack*, and the vulnerability is called an *SQL injection vulnerability*.
+Most database systems include a language that can let you create arbitrary queries, and typically many other functions too (e.g., creating and modifying things). The SQL language is especially common, and while some database systems use other languages, those other languages often have similarities with SQL. Such languages, including SQL, include metacharacters. When attackers can insert metacharacters into a SQL command to cause a security problem, the attack is called an *SQL injection attack*, and the vulnerability is called an *SQL injection vulnerability*. SQL injection is sometimes abbreviated as SQLi.
 
 Even if the database language is not SQL, if it is an attack on a language for a database system it is often called an SQL injection attack (even though this is technically not accurate). We will focus on SQL, because SQL is very common and once you understand how to counter SQL injection attacks, it is easy to generalize this to any database language.