Fix GH-20871: Improve error message for invalid -d options

[khaledalam]

Description

Fixes #20871 by improving error messages for invalid -d command-line options.

Previously, when an invalid -d option was passed to PHP CLI, the error message reported "Unknown on line X". This was confusing for users who don't know about PHP's internal INI handling.

Changes

• Modified Zend/zend_ini_parser.y to detect CLI/FPM -d option parsing context
• When parsing -d options (filename is "Unknown" and unbuffered_errors is true), error messages now report "-d option on line 0" instead of "Unknown on line X"
• Added test case sapi/cli/tests/gh20871.phpt to verify the fix with multiple invalid syntax scenarios

[iluuu1994]

It would probably help even more if there was an indication that the parsing error happens for INI parsing, rather than parsing of the PHP code. For example, instead of "in Unknown" it could print "in INI command line parameter '-d'". Or maybe even the INI line itself.

[khaledalam]

It would probably help even more if there was an indication that the parsing error happens for INI parsing, rather than parsing of the PHP code. For example, instead of "in Unknown" it could print "in INI command line parameter '-d'". Or maybe even the INI line itself.

@iluuu1994 Thank you for the feedback! I've updated the message. The error message now clearly indicates this is INI parsing,

e.g. PHP: syntax error, unexpected '=' in INI command line parameter '-d'