doc: terminology cleanup in secure boot GRUB

- Replace UOS or User OS with User VM
- Replace SOS or Service OS with Service VM
- Clean up some of the grammar

Signed-off-by: Amy Reyes <amy.reyes@intel.com>

doc/tutorials/acrn-secure-boot-with-grub.rst

@@ -5,16 +5,16 @@ Enable ACRN Secure Boot With GRUB
 
 This document shows how to enable ACRN secure boot with GRUB including:
 
--  ACRN Secure Boot Sequence
+-  `ACRN Secure Boot Sequence`_
--  Generate GPG Key
+-  `Generate GPG Key`_
--  Setup Standalone GRUB EFI Binary
+-  `Setup Standalone GRUB EFI Binary`_
--  Enable UEFI Secure Boot
+-  `Enable UEFI Secure Boot`_
 
 **Validation Environment:**
 
-- Hardware Platform: TGL-I7, Supported hardware described in
+- Hardware Platform: Tiger Lake, supported hardware described in
   :ref:`hardware`.
-- ACRN Scenario: Industry
+- ACRN Scenario: Shared
 - Service VM: Yocto & Ubuntu
 - GRUB: 2.04
 
@@ -25,7 +25,7 @@ This document shows how to enable ACRN secure boot with GRUB including:
 ACRN Secure Boot Sequence
 *************************
 
-ACRN can be booted by Multiboot compatible bootloader, following diagram
+ACRN can be booted by a multiboot compatible bootloader. The following diagram
 illustrates the boot sequence of ACRN with GRUB:
 
 .. image:: images/acrn_secureboot_flow.png
@@ -41,10 +41,10 @@ From a secureboot point of view:
 - GRUB verifies ACRN, Service VM kernel, and pre-launched User VM kernel
 - Service VM OS kernel verifies the Device Model (``acrn-dm``) and User
   VM OVMF bootloader (with the help of ``acrn-dm``)
-- User VM virtual bootloader (e.g. OVMF) starts the guest side verified boot process
+- User VM virtual bootloader (e.g., OVMF) starts the guest side verified boot process
 
 This document shows you how to enable GRUB to
-verify ACRN binaries such ``acrn.bin``, Service VM kernel (``bzImage``), and
+verify ACRN binaries such as ``acrn.bin``, Service VM kernel (``bzImage``), and
 if present, a pre-launched User VM kernel image.
 
 .. rst-class:: numbered-step
@@ -185,9 +185,9 @@ For example::
 
 Use the output of the :command:`blkid` to find the right values for the
 UUID (``--set``) and PARTUUID (``root=PARTUUID=`` parameter) of the root
-partition (e.g. `/dev/nvme0n1p2`) according to your your hardware.
+partition (e.g., ``/dev/nvme0n1p2``) according to your hardware.
 
-Copy this new :file:`grub.cfg` to your ESP (e.g. `/boot/efi/EFI/`).
+Copy this new :file:`grub.cfg` to your ESP (e.g., ``/boot/efi/EFI/``).
 
 
 Sign grub.cfg and ACRN Binaries
@@ -196,11 +196,11 @@ Sign grub.cfg and ACRN Binaries
 The :file:`grub.cfg` and all ACRN binaries that will be loaded by GRUB
 **must** be signed with the same GPG key.
 
-Here's sequence example of signing the individual binaries::
+Here's a sequence example of signing the individual binaries::
 
     gpg --homedir keys --detach-sign path/to/grub.cfg
     gpg --homedir keys --detach-sign path/to/acrn.bin
-    gpg --homedir keys --detach-sign path/to/sos_kernel/bzImage
+    gpg --homedir keys --detach-sign path/to/service_vm_kernel/bzImage
 
 Now, you can reboot and the system will boot with the signed GRUB EFI binary.
 GRUB will refuse to boot if any files it attempts to load have been tampered
@@ -246,6 +246,8 @@ The keys to sign bootloader image: :file:`grubx64.efi`, :file:`db.key` , :file:`
 Sign GRUB Image With db Key
 ===========================
 
+Command example::
+
     sbsign --key db.key --cert db.crt path/to/grubx64.efi
 
 :file:`grubx64.efi.signed` will be created, it will be your bootloader.