fix(guide): Fix format isssues with debugging.mdx

Signed-off-by: huyang531 <[email protected]>

content/guides/debugging.mdx

@@ -361,7 +361,7 @@ app-helloworld/
 
 For instructions on building `app-hellworld` using the manual method, see the [application README](https://github.com/unikraft/app-helloworld).
 
-#### Linuxu
+#### On Linuxu
 
 For the image for the **linuxu** platform we can use GDB directly with the binary already created because
 the resulting image is an actual Linux binary.
@@ -370,7 +370,7 @@ the resulting image is an actual Linux binary.
 gdb build/app-helloworld_linuxu-x86_64.dbg
 ```
 
-#### KVM
+#### On KVM
 
 To avoid using a command with a lot of parameters that you noticed above in the **KVM** section, we can use [the `qemu-guest` script](https://github.com/unikraft/unikraft/blob/staging/support/scripts/qemu-guest).
 
@@ -488,7 +488,7 @@ Follow these steps:
 
 1. Investigate memory addresses (using the `x` instruction - such as `x/s $rbp-0x120`), do instruction stepping (`stepi` or `nexti`), use breakpoints (`break *<address>`) and find out the secret.
 
-### 03.	 Bug or feature?
+### 03. Bug or Feature
 
 There are two kernel images located in the `03-bug-or-feature` folder.
 One of them is build for **Linuxu**, the other for **KVM**.
@@ -501,7 +501,7 @@ After you figure out what is happening with the **Linuxu** image, have a look at
 It was built from the code source, but when you will try to run it, you will not get a segmentation fault.
 Is this a bug or a feature?
 
-#### Support Instructions
+#### Support Instruction
 
 Use the `connect.sh` and `debug.sh` scripts located in the task directory for debugging a Unikraft instance.
 
@@ -544,7 +544,7 @@ Follow these steps:
 
 1. Deduce what the issue is.
 
-### 04. Nginx with or without main? That's the question
+### 04. Nginx with or without main - That's the question
 
 Let's try a new application based on networking, **Nginx**.