Add code block in README

README.md

@@ -7,6 +7,7 @@ x86_64 Linux assembly"*
 To learn something new.
 
 # Tree
+```
 .
 ├── 1_false/
 │   ├── Makefile
@@ -24,6 +25,7 @@ To learn something new.
 │   └── src/
 │       └── argc.s
 └── README
+```
 
 # How do I Use This?
 ## Assemble and Link