improve 2020 year README.md files

Do not put author information into a code block.

Made some of the common markdown more consistent.

2020/yang/README.md

@@ -1,9 +1,7 @@
 # Best abuse of CPP
 
-```
 Don Yang  
 <http://uguu.org/>  
-```
 
 ## To build:
 
@@ -13,6 +11,12 @@ make
 
 ### To run:
 
+```sh
+./prog [PIN] < input.txt > output.c
+```
+
+### Try:
+
 ```sh
 echo "International Obfuscated C Code Contest 2020" | ./prog 23209 > code.c