st-flash: adjust formatting (#18521)

Author: Sarijen

pages/common/st-flash.md

@@ -5,11 +5,11 @@
 
 - Read 4096 bytes from the device starting from 0x8000000:
 
-`st-flash read {{firmware}}.bin {{0x8000000}} {{4096}}`
+`st-flash read {{firmware}}.bin 0x8000000 4096`
 
 - Write firmware to device starting from 0x8000000:
 
-`st-flash write {{firmware}}.bin {{0x8000000}}`
+`st-flash write {{firmware}}.bin 0x8000000`
 
 - Erase firmware from device: