build: Replace 'make download' with 'make flash'

Documentation/platforms/risc-v/esp32c3/index.rst

@@ -58,14 +58,14 @@ The `esptool.py` command to flash all the binaries is::
 
 However, this is also included in the build process and we can build and flash with::
 
-   make download ESPTOOL_PORT=<port> ESPTOOL_BINDIR=../esp-bins
+   make flash ESPTOOL_PORT=<port> ESPTOOL_BINDIR=../esp-bins
 
 Where ``<port>`` is typically ``/dev/ttyUSB0`` or similar and ``../esp-bins`` is 
 the path to the folder containing the bootloader and the partition table
 for the ESP32-C3 as explained above.
 Note that this step is required only one time.  Once the bootloader and partition
 table are flashed, we don't need to flash them again.  So subsequent builds
-would just require: ``make download ESPTOOL_PORT=/dev/ttyUSBXX``
+would just require: ``make flash ESPTOOL_PORT=/dev/ttyUSBXX``
 
 Debugging with OpenOCD
 ======================

Documentation/platforms/xtensa/esp32/index.rst

@@ -60,7 +60,7 @@ It's a two step process where the first converts the ELF file into a ESP32-compa
 and the second flashes it to the board.  These steps are included into the build system and you can
 flash your NuttX firmware simply by running::
 
-    $ make download ESPTOOL_PORT=<port>
+    $ make flash ESPTOOL_PORT=<port>
 
 where ``<port>`` is typically ``/dev/ttyUSB0`` or similar. You can change the baudrate by passing ``ESPTOOL_BAUD``.
 
@@ -73,7 +73,7 @@ Once you downloaded both binaries, you can flash them by adding an ``ESPTOOL_BIN
 
 .. code-block:: console
 
-   $ make download ESPTOOL_PORT=<port> ESPTOOL_BINDIR=<dir>
+   $ make flash ESPTOOL_PORT=<port> ESPTOOL_BINDIR=<dir>
 
 .. note:: It is recommended that if this is the first time you are using the board with NuttX that you perform a complete
    SPI FLASH erase.