Add Google Pixel 3a/XL markdown

Change-Id: I3f4c1335735c3babfa7a2c4ea97954cda37b8594
diff --git a/_google/googlepixel3axl.markdown b/_google/googlepixel3axl.markdown
new file mode 100644
index 0000000..bed3218
--- /dev/null
+++ b/_google/googlepixel3axl.markdown
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+---
+layout: device
+title:  "Google Pixel 3a XL"
+codename: bonito
+downloadfolder: bonito
+supportstatus: Current
+maintainer: ZVNexus
+oem: Google
+devicetree: https://github.com/TeamWin/android_device_google_bonito
+---
+
+{% include disclaimer.html %}
+
+{% include supportstatus.html %}
+Please note that you cannot install this on stock, unless you are running a kernel that supports LZMA compression.
+
+{% include download.html %}
+
+<div class='page-heading'>Installation:</div>
+If you already have TWRP installed:
+Download the latest zip and install the zip using TWRP.
+
+If you do not already have TWRP installed:
+Download both the img and the zip. You will need to have fastboot binaries and the correct drivers installed. Power off your device completely. Hold volume down and turn on the device. Your device should now be in the bootloader. Connect the device to your PC. Open a command window and run the following command from the proper location:
+
+fastboot boot path/to/twrp.img
+
+This will temporarily boot TWRP on your device. Use ADB or MTP to push the zip to your device.
+
+Go to install and browse to the zip and install the zip. The zip will install TWRP to both boot slots. Installing TWRP at this time will remove root if you are currently rooted.
+
+If you accidently flash TWRP to your device using fastboot instead of temporarily booting the image, you will need to download the latest factory image for your device and reflash the boot image.