Understanding Oracle "LOG_ARCHIVE_START" parameter
First of all, the documentation that you have referenced are not from Oracle 12c, one is from Oracle 9i and another one is not the official documentation. 

Second of all, the parameter log_archive_start is deprecated in Oracle 10g, meaning no longer available in the next release. 


  Starting with Oracle Database 10g Release 1 (10.1), the LOG_ARCHIVE_START initialization parameter has been deprecated. Archiving is now automatically started when the database is placed in ARCHIVELOG mode.


Database Upgrade Guide 10g

Finally, You can use the following query to select all the deprecated parameters.

SQL&gt; SELECT name from v$parameter 
     WHERE isdeprecated = 'TRUE' ORDER BY name;


Documentation: Deprecated and Desupported Features