fix typos

installing/live-usb.md

@@ -20,7 +20,7 @@ We have faced several challenges when making this Live USB edition of Qubes OS,
 which traditional Linux distros don't have to bother with:
 
 1. We needed to ensure Xen is properly started when booting the stick. In fact
-   we still don't support UEFI boot for the sitck for this reason, even though
+   we still don't support UEFI boot for the stick for this reason, even though
    the Fedora liveusb creator we used does support it. Only legacy boot for this
    version, sorry.
 2. We discovered that the Fedora liveusb-create does *not* verify signatures on

installing/multiboot.md

@@ -21,7 +21,7 @@ Read the [guidelines](/doc/security-guidelines) carefully.
 One problem is that when you dual or multiboot, even if you are using
 encryption on your Qubes installation, /boot is still unprotected and
 could be maliciously modified by the other OS, possibly leading to Qubes
-itself being maliciously modifed.
+itself being maliciously modified.
 
 The other problem is firmware security - for example the other system
 could infect BIOS firmware, which might enable compromise or spying on
@@ -177,8 +177,8 @@ sudo grub2-mkconfig -o /boot/grub2/grub.cfg
 Troubleshooting
 ----------------------
 
-If you install Qubes without making any backups beforehand, dont worry.  
-If you didnt overwrite the original partitions, then it is usually
+If you install Qubes without making any backups beforehand, don't worry.
+If you didn't overwrite the original partitions, then it is usually
 possible to recover your old systems relatively easily, as described above.
 
 If you decided to use a shared /boot and *dont* have backups of your previous