Fix bare urls in markdown

content/posts/adventofctf/challenge_19.md

@@ -27,7 +27,7 @@ categories = [
 
 We found out that it was possible to insert Javascript code in the calculator. Oops! We found an awesome module to prevent against this abuse. Hopefully it is all better now. The flag is in flag.txt.
 
-Visit https://19.adventofctf.com to start the challenge.
+Visit <https://19.adventofctf.com> to start the challenge.
 
 ## Recon
 

content/posts/adventofctf/challenge_20.md

@@ -27,7 +27,7 @@ categories = [
 
 To pass the time until Christmas the elves challenge Santa to a game of tic-tac-toe. Santa plays X, can you make him win?
 
-Visit https://20.adventofctf.com to start the challenge.
+Visit <https://20.adventofctf.com> to start the challenge.
 
 ## Recon
 

content/posts/adventofctf/challenge_21.md

@@ -28,7 +28,7 @@ We are testing a new mechanism to filter out malicious content from URLs. This a
 
 The flag is in /flag.txt
 
-Visit https://21.adventofctf.com to start the challenge.
+Visit <https://21.adventofctf.com> to start the challenge.
 
 ## Recon
 

content/posts/adventofctf/challenge_22.md

@@ -27,7 +27,7 @@ categories = [
 
 We have a new service! You can view santa's favorite pictues. Currently there is only one, but it is a very good one! You can get the flag through flag.php.
 
-Visit https://22.adventofctf.com to start the challenge.
+Visit <https://22.adventofctf.com> to start the challenge.
 
 ## Recon
 

content/posts/adventofctf/challenge_23.md

@@ -26,7 +26,7 @@ categories = [
 
 If all you do is talk, there are bound to be secret features. The flag is stored in /flag.txt.
 
-Visit https://23.adventofctf.com to start the challenge.
+Visit <https://23.adventofctf.com> to start the challenge.
 
 ## Recon