docs: Ulpdated ULP docs to have the correct notes directive

This commit updates the ULP .rst files to have the correct notes
directive format. The notes directives were missing a colon.

docs/en/api-reference/system/ulp.rst

@@ -34,7 +34,7 @@ To compile the ULP FSM code as part of the component, the following steps must b
 
 1. The ULP FSM code, written in assembly, must be added to one or more files with `.S` extension. These files must be placed into a separate directory inside the component directory, for instance, `ulp/`.
 
-.. note: When registering the component (via ``idf_component_register``), this directory should not be added to the ``SRC_DIRS`` argument. The logic behind this is that the ESP-IDF build system will compile files found in ``SRC_DIRS`` based on their extensions. For ``.S`` files, ``{IDF_TARGET_TOOLCHAIN_PREFIX}-as`` assembler is used. This is not desirable for ULP FSM assembly files, so the easiest way to achieve the distinction is by placing ULP FSM assembly files into a separate directory. The ULP FSM assembly source files should also **not** be added to ``SRCS`` for the same reason. See the step below for how to properly add ULP FSM assembly source files.
+.. note:: When registering the component (via ``idf_component_register``), this directory should not be added to the ``SRC_DIRS`` argument. The logic behind this is that the ESP-IDF build system will compile files found in ``SRC_DIRS`` based on their extensions. For ``.S`` files, ``{IDF_TARGET_TOOLCHAIN_PREFIX}-as`` assembler is used. This is not desirable for ULP FSM assembly files, so the easiest way to achieve the distinction is by placing ULP FSM assembly files into a separate directory. The ULP FSM assembly source files should also **not** be added to ``SRCS`` for the same reason. See the step below for how to properly add ULP FSM assembly source files.
 
 2. Call ``ulp_embed_binary`` from the component CMakeLists.txt after registration. For example::