The former FLASH_MODE_{DOUT,DIO,QOUT,QIO} defines are replaced by the corresponding CONFIG_FLASHMODE_{DOUT,DIO,QOUT,QIO} and CONFIG_ESPTOOLPY_FLASHMODE_{DOUT,DIO,QOUT,QIO} as used by the ESP-IDF. This is also needed for the migration of defining flash mode in Kconfig.
Fixes various issues in documentation:
- replaces HTML anchor tags in markdown headings by markdown heading IDs.
- replaces HTML linebreaks by newline commands
- replaces \htmlonly commands for image resizing by the width argument in \image commands
- uses more unique identifiers for references
- uses stable references for driver documentation
- fix broken links to external HTML documents
- replaces the TOC link in headers by a back to TOC link below each section
- replaces ``` fenced code blocks by ~~~
Instead of using the same MCU feature table in every board documentation, it refers to the MCU documentation. This makes it easier to maintain the MCU feature table.
SPI0_DEV and SPI1_DEV configuration parameters are renamed SPI0_CTRL and SPI1_CTRL to better describe what they define and to avoid confusion with SPI_DEV (0) and SPI_DEV (1).
Fixes the UART pin configuration for UART_DEV(0). Since this configuration is fixed and only defined for documentation purposes, the change has no impact on the code.
