Typo in README (#503)

Changed "Is is generated..." to "It is generated...".

Author: reflektoin

README.md

@@ -16,7 +16,7 @@ SQLite is public domain, sql.js is MIT licensed.
 
 ## API documentation
 A [full API documentation](https://sql.js.org/documentation/) for all the available classes and methods is available.
-Is is generated from comments inside the source code, and is thus always up to date.
+It is generated from comments inside the source code, and is thus always up to date.
 
 ## Usage