[Documentation] Markdown improvements f to m (#13866)

Signed-off-by: Jerome Luckenbach <github@luckenba.ch>

bundles/org.openhab.binding.gpio/README.md

@@ -1,7 +1,7 @@
 # GPIO Binding
 
 This binding adds GPIO support via the pigpio daemon to openhab.
-It requires the pigpio (http://abyz.me.uk/rpi/pigpio/) to be running on the pi that should be controlled.
+It requires the pigpio (<http://abyz.me.uk/rpi/pigpio/>) to be running on the pi that should be controlled.
 
 ## Supported Things
 
@@ -15,7 +15,7 @@ This thing represents a remote pigpio instance running as daemon on a raspberry
 
 On a raspberry (or a compatible device) you have to install pigpio:
 
-```
+```shell
 sudo apt-get install pigpiod
 sudo raspi-config 
 ```
@@ -24,22 +24,24 @@ sudo raspi-config
 
 Note: if you are setting this up on a Raspberry Pi without `raspi-config` you can create the service config file manually:
 
-```
+```shell
 sudo mkdir -p /etc/systemd/system/pigpiod.service.d/
 sudo nano /etc/systemd/system/pigpiod.service.d/public.conf
 ```
 
-    [Service]
-    ExecStart=
-    ExecStart=/usr/bin/pigpiod
-
+```text
+[Service]
+ExecStart=
+ExecStart=/usr/bin/pigpiod
 ```
+
+```shell
 sudo systemctl daemon-reload
 ```
 
 Now that Remote GPIO is enabled, get the daemon going (even if installed with apt-get):
 
-```
+```shell
 sudo systemctl enable pigpiod 
 sudo systemctl start pigpiod
 ```
@@ -71,10 +73,9 @@ If you want to invert the value, set `invert` to true.
 
 ## Full Example
 
-
 demo.things:
 
-```
+```java
 Thing gpio:pigpio-remote:sample-pi-1 "Sample-Pi 1" [host="192.168.2.36", port=8888] {
     Channels:
         Type pigpio-digital-input : sample-input-1 [ gpioId=10]
@@ -92,14 +93,14 @@ Thing gpio:pigpio-remote:sample-pi-2 "Sample-Pi 2" [host="192.168.2.37", port=88
 
 demo.items:
 
-```
+```java
 Switch SampleInput1 {channel="gpio:pigpio-remote:sample-pi-1:sample-input-1"}
 Switch SampleOutput1 {channel="gpio:pigpio-remote:sample-pi-1:sample-output-1"}
 ```
 
 demo.sitemap:
 
-```
+```perl
 sitemap demo label="Main Menu"
 {
     Switch item=SampleInput1