Update H4

exercises/h4.md

@@ -272,7 +272,7 @@ newuser@goauldhost:~$ mkdir -p ./source_codes/apache2 && cd ./source_codes/apach
 newuser@goauldhost:~/source_codes/apache2$ apt-get source apache2
 ```
 
-After which add [source code patch file](https://github.com/Fincer/linux-server-setup/blob/master/patches/patch_apache_servertokens.patch) into created `$HOME/source_codes/apache2` folder.
+After which add [source code patch file](https://raw.githubusercontent.com/Fincer/linux-server-setup/master/patches/patch_apache_servertokens.patch) into created `$HOME/source_codes/apache2` folder.
 
 **NOTE:** I have personally created the patch file with Unix tool `diff`. The patch file is not downloaded from any suspicious website. You can always check & analyse the patch file code yourself if still hesitating.
 
@@ -305,6 +305,7 @@ newuser@goauldhost:~/source_codes/apache2/apache2-2.4.18$ sudo apt-get install d
 
 Compile and install the Apache web server:
 
+```
 newuser@goauldhost:~/source_codes/apache2/apache2-2.4.18$ dpkg-buildpackage -rfakeroot -b -us -uc
 ...
 <compiling source code>