Fix typo in documentation
Fix typo in documentation

In the part "Generating Migrations Automatically" there is a mapping
information sample for creating a new User entity. On the "Annotations"
tab the "name" property has a length of "255".

Having those double quotes around 255 is incorrect because running
"app/console doctrine:migrations:diff" throws an error. It expects
"length" to be an integer and not a string.

I removed the double quotes to prevent this error.

doctrine/DoctrineMigrationsBundle