Description:

Add documentation for the new disable_libc_locks_in_iram advanced configuration option for ESP32. This option allows users to save approximately 1.3KB of IRAM by disabling the placement of libc lock functions in internal RAM.

The documentation explains:

• What the option does and why it's beneficial (saves ~1.3KB IRAM)
• That it's enabled by default (IRAM placement disabled to save RAM)
• When users might need to disable it (external components using libc locks in IRAM ISRs)
• That it only applies to ESP-IDF framework

Related issue (if applicable): N/A

Pull request in esphome with YAML changes (if applicable):

• [esp32] Add option to disable libc locks in IRAM, saving ~1.3KB RAM esphome#10930

Checklist:

• I am merging into next because this is new documentation that has a matching pull-request in esphome as linked above.
  or

• I am merging into current because this is a fix, change and/or adjustment in the current documentation and is not for a new component or feature.

• Link added in /components/index.rst when creating new documents for new components or cookbook.