docs: Add --no-snapshot option in the man pages

docs/man/snf-image-creator.rst

@@ -23,5 +23,8 @@ Options
 	show this help message and exit
 -l FILE, --logfile=FILE
 	log all messages to FILE
+--no-snapshot
+	don't snapshot the input media. (THIS IS DANGEROUS AS IT WILL ALTER THE
+	ORIGINAL MEDIA!!!)
 --tmpdir=DIR
 	create large temporary image files under DIR

docs/man/snf-mkimage.rst

@@ -44,6 +44,9 @@ Options
 --no-shrink
 	don't shrink any partition
 
+--no-snapshot
+	don't snapshot the input media. (THIS IS DANGEROUS AS IT WILL ALTER THE
+	ORIGINAL MEDIA!!!)
 --no-sysprep
 	don't perform any system preparation operation