Update CAR INSTALL.md

Author: mikebrady

CAR INSTALL.md

@@ -201,7 +201,7 @@ fi
 exit 0 # normal exit here
 ```
 
-#### Disable Unused Services (Optional)
+#### Disable Unused Services - Optional
 These optional steps have been tested on a Raspberry Pi only -- they have not been tested on other systems.
 Some services are not necessary for this setup and can be disabled as follows:
 ```
@@ -211,7 +211,7 @@ Some services are not necessary for this setup and can be disabled as follows:
 ```
 
 
-#### Disable Unused Services (Mandatory)
+#### Disable Unused Services - Mandatory
 You now need to disable some services; that is, you need to stop them starting automatically on power-up. This is because they either interfere with the system's operation in WiFi Access Point mode, or because they won't work when the system isn't connected to the Internet. Only one of the `NetworkManager` and the `dhcpcd` service will be present in your system, but it's no harm to try to disable both.
 ```
 # systemctl disable dhcpcd
@@ -247,7 +247,7 @@ However, if you're *upgrading* the operating system to e.g. from Bullseye to Boo
 If it's a Raspberry Pi and you have optionally enabled the read-only mode, you must take the device out of Read-only mode:  
 Run `sudo raspi-config` and then choose `Performance Options` > `Overlay Filesystem` and choose to disable the overlay filesystem and to set the boot partition not to be write-protected. This is so that changes can be written to the file system; you can make the filesystem read-only again later. Save the changes and reboot the system.
 #### Undo Optimisations
-If you have disabled any of the services listed in the [Disable Unused Services](#disable-unused-services) section, you should re-enable them. (But *do not* re-eneable `NetworkManager`, `dhcpcd`, `wpa_supplicant` or `systemd-timesyncd` -- they are handled specially by the startup script.)
+If you have disabled any of the services listed in the [Disable Unused Services - Optional](#disable-unused-services---optional) section, you should re-enable them. (But *do not* re-eneable `NetworkManager`, `dhcpcd`, `wpa_supplicant` or `systemd-timesyncd` -- they are handled specially by the startup script.)
 #### Perform Legacy Updates
 Over time, the arrangements by which the system is prepared for operation has changed to make it easier to revert to normal operation when necessary for maintenance, updates, etc. A small number of the old settings need to be changed to bring them up to date with the present arrangements. Once the required changes have been made, your system will be ready for the update process detailed below. Here are those legacy changes you need to make, just once: