doc: ti: update bash code-block directives to prompt

The code-block directive requires addition of the prompt symbol for each
line, using the prompt directive instead allows for auto insertion of
the symbol per line[1].

For the readers, the character added by the prompt directive is
un-selectable i.e the entire line can be more easily selected for copy
pasting etc. Whereas with code-block, the prompt symbol like "$" is also
selectable which is usually not the intent.

This is mostly a QoL addition + making the docs consistent since k3.rst
makes use of prompt directives which these board docs include from.

[1]: https://pypi.org/project/sphinx-prompt/

Signed-off-by: Anshul Dalal <anshuld@ti.com>
diff --git a/doc/board/ti/j784s4_evm.rst b/doc/board/ti/j784s4_evm.rst
index a1e927c..349fb39 100644
--- a/doc/board/ti/j784s4_evm.rst
+++ b/doc/board/ti/j784s4_evm.rst
@@ -81,14 +81,14 @@
 .. include::  k3.rst
     :start-after: .. k3_rst_include_start_common_env_vars_defn
     :end-before: .. k3_rst_include_end_common_env_vars_defn
-.. code-block:: bash
+.. prompt:: bash
 
- $ export UBOOT_CFG_CORTEXR=j784s4_evm_r5_defconfig
- $ export UBOOT_CFG_CORTEXA=j784s4_evm_a72_defconfig
- $ export TFA_BOARD=j784s4
- $ export TFA_EXTRA_ARGS="K3_USART=0x8"
- $ export OPTEE_PLATFORM=k3-j784s4
- $ export OPTEE_EXTRA_ARGS="CFG_CONSOLE_UART=0x8"
+   export UBOOT_CFG_CORTEXR=j784s4_evm_r5_defconfig
+   export UBOOT_CFG_CORTEXA=j784s4_evm_a72_defconfig
+   export TFA_BOARD=j784s4
+   export TFA_EXTRA_ARGS="K3_USART=0x8"
+   export OPTEE_PLATFORM=k3-j784s4
+   export OPTEE_EXTRA_ARGS="CFG_CONSOLE_UART=0x8"
 
 .. j784s4_evm_rst_include_start_build_steps
 
@@ -326,6 +326,6 @@
 To start OpenOCD and connect to J784S4-EVM or AM69-SK board, use the
 following.
 
-.. code-block:: bash
+.. prompt:: bash
 
   openocd -f board/ti_j784s4evm.cfg