docs: Fix word repetition in pci-addresses.rst

Fixes: 2923e7a3Reported-by: NJán Tomko <jtomko@redhat.com>
Signed-off-by: NAndrea Bolognani <abologna@redhat.com>

docs/pci-addresses.rst

@@ -4,7 +4,7 @@ PCI addresses in domain XML and guest OS
 
 .. contents::
 
-When discussing PCI addresses, it's important to understand the the
+When discussing PCI addresses, it's important to understand the
 relationship between the addresses that can be seen in the domain XML
 and those that are visible inside the guest OS.