[psram] Document new ignore_not_found option (#5502)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

Author: kahrendt

content/components/psram.md

@@ -33,6 +33,10 @@ psram:
 - **disabled** (*Optional*, bool): Don't try to initialize the PSRAM. This is needed if one of the configured components autoloads psram
   but the ESP32 module doesn't have PSRAM and you need to use one of the PSRAM control lines for something else. e.g. ethernet. Defaults to ``false``.
 
+- **ignore_not_found** (*Optional*, bool): When ``true`` (default), the firmware ignores PSRAM initialisation failures and continues to boot.
+  When ``false``, other components can configure larger WiFi buffers for faster data transfer, but **PSRAM must be available or the device will
+  fail to boot.**
+
 ## Modes
 
 The ESP32 PSRAM is only available in `quad` mode, and ESP32-P4 only supports `hex` mode. These are the defaults