ncsi-coredump: fix typo

Change-Id: I828eb8ffd93eccdad7529ea2919228ac4ff76c29
Signed-off-by: Jagpal Singh Gill <paligill@gmail.com>
diff --git a/designs/ncsi-coredump.md b/designs/ncsi-coredump.md
index c0e8624..6d91ac8 100644
--- a/designs/ncsi-coredump.md
+++ b/designs/ncsi-coredump.md
@@ -29,7 +29,7 @@
 ### Interface
 
 This design will reuse existing phosphor-debug-collector module:
-<https://github.com/openbmc/phosphor-debug-collector> and extent the dump
+<https://github.com/openbmc/phosphor-debug-collector> and extend the dump
 creation interface with a new "NC-SICoreDump" dump type.
 
 The D-Bus interface for dump creation will be:"xyz.openbmc_project.Dump.Manager