doc, coding guidelines: fix cert-c links in coding guidelines
doc, coding guidelines: fix cert-c links in coding guidelines

Fixes broken links to CERT-C in Coding Guidelines.

Fixes #35195

Signed-off-by: Lauren Murphy <ce8d3478b631de4cc130a07ddd0282d1734fed61@intel.com>

zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr