docs: Add syntax highlighting to more code blocks

Added language tags to more code blocks in the documentation to enable
syntax highlighting.

docs/blog/2022-04-02-zephyr-3-0.md

@@ -29,12 +29,12 @@ Existing user config repositories using Github Actions to build will pull down Z
 - Change `zmkfirmware/zmk-build-arm:2.5` to `zmkfirmware/zmk-build-arm:stable` wherever it is found
 - Locate and delete the lines for the DTS output step, which is no longer needed:
 
-  ```
-    - name: ${{ steps.variables.outputs.display-name }} DTS File
-      if: ${{ always() }}
-      run: |
-        if [ -f "build/zephyr/${{ matrix.board }}.pre.tmp" ]; then cat -n build/zephyr/${{ matrix.board }}.pre.tmp; fi
-        if [ -f "build/zephyr/zephyr.dts" ]; then cat -n build/zephyr/zephyr.dts; fi
+  ```yaml
+  - name: ${{ steps.variables.outputs.display-name }} DTS File
+    if: ${{ always() }}
+    run: |
+      if [ -f "build/zephyr/${{ matrix.board }}.pre.tmp" ]; then cat -n build/zephyr/${{ matrix.board }}.pre.tmp; fi
+      if [ -f "build/zephyr/zephyr.dts" ]; then cat -n build/zephyr/zephyr.dts; fi
   ```
 
 :::note
@@ -76,7 +76,7 @@ The following changes have [already been completed](https://github.com/zmkfirmwa
 
 Zephyr's WS2812 `led_strip` driver added a new required property. When adding [underglow](/docs/features/underglow#adding-rgb-underglow-to-a-board) to a board, you now must also add the additional include `#include <dt-bindings/led/led.h>` at the top of your devicetree file, and add a `color-mapping` property like:
 
-```
+```dts
 led_strip: ws2812@0 {
   compatible = "worldsemi,ws2812-spi";
   label = "WS2812";
@@ -108,7 +108,7 @@ Zephyr moved to using a `chosen` node named `zephyr,display` to select the displ
 
 For example, for a shield with:
 
-```
+```dts
 &pro_micro_i2c {
   status = "okay";
 
@@ -132,7 +132,7 @@ For example, for a shield with:
 
 You would add a `chosen` node like:
 
-```
+```dts
 / {
   chosen {
     zephyr,display = &oled;
@@ -148,7 +148,7 @@ two sections of the `<board>.dts` file need updating.
 
 Underneath the USB device, add the CDC ACM node:
 
-```
+```dts
 &usbd {
   status = "okay";
   cdc_acm_uart: cdc_acm_uart {
@@ -160,7 +160,7 @@ Underneath the USB device, add the CDC ACM node:
 
 Then, an additional `chosen` node (near the top of the file) will mark the CDC ACM device as the console:
 
-```
+```dts
 / {
   chosen {
     ...
@@ -175,7 +175,7 @@ Then, an additional `chosen` node (near the top of the file) will mark the CDC A
 Previously, to get ZMK to build a UF2 image to flash to a given board required adding a `CMakeLists.txt` file that added a custom post build command.
 Now, the only thing necessary to have Zephyr build a UF2 is to add the following to your `<board>_defconfig` file:
 
-```
+```ini
 CONFIG_BUILD_OUTPUT_UF2=y
 ```
 
@@ -187,7 +187,7 @@ For more details on the implementation, see [zephyr#31066](https://github.com/ze
 
 Clock configuration moved to devicetree as well, out of the Kconfig files. Here is a sample config for a board that uses the HSI for the PLL source:
 
-```
+```dts
 &clk_hsi {
   status = "okay";
 };