WP_Locale add get_month_genitive() method

[Tkama]

The WP_Locale class has get_month() and get_month_abbrev() methods, but does not have get_month_genitive(). It should be there as well.

We should add such a code:

	/**
	 * Retrieves the full translated month in genitive case by month number.
	 *
	 * @since 6.2.3
	 *
	 * @param string|int $month_number  From 1 to 12. If a number less than 10 is
	 *                                  passed in integer or string format, a '0' will be added before it.
	 *
	 * @return string Translated full month name in genitive case.
	 */
	public function get_month_genitive( $month_number ) {
		return $this->month_genitive[ zeroise( $month_number, 2 ) ];
	}

[SergeyBiryukov]

Thanks for the ticket! Setting the version to 4.4 as per [35517] / #11226.

Trac Ticket: Core-58658

### Summary

This pull request introduces a new utility function, get_month_genitive(), in the WP_Locale class to enhance localization capabilities. This function provides the genitive form of month names, which is necessary for languages that require different grammatical cases depending on context. The function accepts a month number as a string (e.g., ‘01’ for January) or an integer (e.g., 1 for January), and zero-pads numbers less than 10 automatically when an integer is provided.

### Changes

Added get_month_genitive() Function:

• The function accepts month numbers from ‘01’ to ‘12’ as a string or as an integer from 1 to 12.
• If provided as an integer, the function pads single-digit months to two digits automatically, ensuring consistent formatting.
• Returns the translated month name in genitive case based on the site locale.

### Benefits

• Enhanced Localization: Improves date formatting for languages that require genitive forms, making WordPress output more natural and grammatically correct in languages such as Russian or Polish.
• Flexible Input Handling: The function accommodates both string and integer inputs, providing flexibility and simplifying month number handling.

### Example Usage

// Example of retrieving the genitive form of a month in a localized context.
$date_locale = new WP_Locale();
$genitive_month = $date_locale->get_month_genitive(1); // Outputs 'января' in Russian.

Trac Ticket: core 58658

### Summary

This pull request introduces a new utility function, get_month_genitive(), in the WP_Locale class to enhance localization capabilities. This function provides the genitive form of month names, which is necessary for languages that require different grammatical cases depending on context. The function accepts a month number as a string (e.g., ‘01’ for January) or an integer (e.g., 1 for January), and zero-pads numbers less than 10 automatically when an integer is provided.

### Changes

Added get_month_genitive() Function:

• The function accepts month numbers from ‘01’ to ‘12’ as a string or as an integer from 1 to 12.
• If provided as an integer, the function pads single-digit months to two digits automatically, ensuring consistent formatting.
• Returns the translated month name in genitive case based on the site locale.

### Example Usage

// Example of retrieving the genitive form of a month in a localized context.
$date_locale = new WP_Locale();
$genitive_month = $date_locale->get_month_genitive(1);

[swissspidy]

In 59494:

I18N: Add new WP_Locale::get_month_genitive() method.

Complements existing helper methods such as WP_Locale::get_month_abbrev().

Props ankitkumarshah, Tkama, SergeyBiryukov.
Fixes #58658.

Committed in https://core.trac.wordpress.org/changeset/59494