Readme: Use bold text instead of h3 headings

README.md

@@ -28,7 +28,7 @@ The above command creates a subdirectory named `code` that contains the code for
 
 The goal of this project is to provide step-by-step tutorials in individual blog posts. We currently have the following set of posts:
 
-### Bare Bones
+**Bare Bones:**
 
 - [A Freestanding Rust Binary](https://os.phil-opp.com/freestanding-rust-binary/)
     ([source code](https://github.com/phil-opp/blog_os/tree/post-01))
@@ -37,14 +37,14 @@ The goal of this project is to provide step-by-step tutorials in individual blog
 - [VGA Text Mode](https://os.phil-opp.com/vga-text-mode/)
     ([source code](https://github.com/phil-opp/blog_os/tree/post-03))
 
-### Testing
+**Testing:**
 
 - [Unit Testing](https://os.phil-opp.com/unit-testing/)
     ([source code](https://github.com/phil-opp/blog_os/tree/post-04))
 - [Integration Tests](https://os.phil-opp.com/integration-tests/)
     ([source code](https://github.com/phil-opp/blog_os/tree/post-05))
 
-### Interrupts
+**Interrupts:**
 
 - [CPU Exceptions](https://os.phil-opp.com/cpu-exceptions/)
     ([source code](https://github.com/phil-opp/blog_os/tree/post-06))
@@ -53,19 +53,19 @@ The goal of this project is to provide step-by-step tutorials in individual blog
 - [Hardware Interrupts](https://os.phil-opp.com/hardware-interrupts/)
     ([source code](https://github.com/phil-opp/blog_os/tree/post-08))
 
-### Memory Management
+**Memory Management:**
 
 - [Introduction to Paging](https://os.phil-opp.com/paging-introduction/)
     ([source code](https://github.com/phil-opp/blog_os/tree/post-09))
 - [Advanced Paging](https://os.phil-opp.com/advanced-paging/)
     ([source code](https://github.com/phil-opp/blog_os/tree/post-10))
 
-
 ## First Edition Posts
 
 The current version of the blog is already the second edition. The first edition is outdated and no longer maintained, but might still be useful. The posts of the first edition are:
 
-### Bare Bones
+**Bare Bones:**
+
 - [A Minimal x86 Kernel](https://os.phil-opp.com/multiboot-kernel.html)
       ([source code](https://github.com/phil-opp/blog_os/tree/first_edition_post_1))
 - [Entering Long Mode](https://os.phil-opp.com/entering-longmode.html)
@@ -75,7 +75,8 @@ The current version of the blog is already the second edition. The first edition
 - [Printing to Screen](https://os.phil-opp.com/printing-to-screen.html)
       ([source code](https://github.com/phil-opp/blog_os/tree/first_edition_post_4))
 
-### Memory Management
+**Memory Management:**
+
 - [Allocating Frames](https://os.phil-opp.com/allocating-frames.html)
       ([source code](https://github.com/phil-opp/blog_os/tree/first_edition_post_5))
 - [Page Tables](https://os.phil-opp.com/modifying-page-tables.html)
@@ -85,13 +86,15 @@ The current version of the blog is already the second edition. The first edition
 - [Kernel Heap](https://os.phil-opp.com/kernel-heap.html)
       ([source code](https://github.com/phil-opp/blog_os/tree/first_edition_post_8))
 
-### Exceptions
+**Exceptions:**
+
 - [Handling Exceptions](https://os.phil-opp.com/handling-exceptions.html)
       ([source code](https://github.com/phil-opp/blog_os/tree/first_edition_post_9))
 - [Double Faults](https://os.phil-opp.com/double-faults.html)
       ([source code](https://github.com/phil-opp/blog_os/tree/first_edition_post_10))
 
-### Additional Resources
+**Additional Resources:**
+
 - [Cross Compile Binutils](https://os.phil-opp.com/cross-compile-binutils.html)
 - [Cross Compile libcore](https://os.phil-opp.com/cross-compile-libcore.html)
 - [Set Up GDB](https://os.phil-opp.com/set-up-gdb.html)