boards/nucleo64-f4: add pinout source

Author: krzysztof-cabaj

boards/nucleo-f401re/doc.txt

@@ -14,7 +14,7 @@ STM32F401RE microcontroller with 96KiB of RAM and 512KiB of Flash.
 
 ## Pinout
 
-@image html pinouts/nucleo-f401re.svg "Pinout for the nucleo-f401re" width=50%
+@image html pinouts/nucleo-f401re.svg "Pinout for the Nucleo-F401RE (from STM user manual UM1724, http://www.st.com/resource/en/user_manual/dm00105823.pdf, page 32)" width=50%
 
 ### MCU
 

boards/nucleo-f410rb/doc.txt

@@ -14,7 +14,7 @@ STM32F410RB microcontroller with 32KiB of RAM and 128KiB of Flash.
 
 ## Pinout
 
-@image html pinouts/nucleo-f410rb.svg "Pinout for the nucleo-f410rb" width=50%
+@image html pinouts/nucleo-f410rb.svg "Pinout for the Nucleo-F410RB (from STM user manual UM1724, http://www.st.com/resource/en/user_manual/dm00105823.pdf, page 36)" width=50%
 
 ### MCU
 

boards/nucleo-f411re/doc.txt

@@ -14,7 +14,7 @@ STM32F411RE microcontroller with 128KiB of RAM and 512KiB of Flash.
 
 ## Pinout
 
-@image html pinouts/nucleo-f411re.svg "Pinout for the nucleo-f411re" width=50%
+@image html pinouts/nucleo-f411re.svg "Pinout for the Nucleo-F411RE (from STM user manual UM1724, http://www.st.com/resource/en/user_manual/dm00105823.pdf, page 32)" width=50%
 
 ### MCU
 

boards/nucleo-f446re/doc.txt

@@ -14,7 +14,7 @@ STM32F446RE microcontroller with 128KiB of RAM and 512KiB of Flash.
 
 ## Pinout
 
-@image html pinouts/nucleo-f446re.svg "Pinout for the nucleo-f446re" width=50%
+@image html pinouts/nucleo-f446re.svg "Pinout for the Nucleo-F446RE (from STM user manual UM1724, http://www.st.com/resource/en/user_manual/dm00105823.pdf, page 35)" width=50%
 
 ### MCU