internal/vulncheck/internal/gosym: fix typo

Causes a test failure that breaks the longtest build. Which I guess only
runs on LUCI.

Change-Id: If40b6dea9c97124ee594c2ddf10ebd996b929971
Reviewed-on: https://go-review.googlesource.com/c/vuln/+/518715
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Commit-Queue: Heschi Kreinick <heschi@google.com>
Auto-Submit: Heschi Kreinick <heschi@google.com>

internal/vulncheck/internal/gosym/additions_test.go

@@ -26,7 +26,7 @@ func TestFuncSymName(t *testing.T) {
 		{"go1.20", funcSymNameGo120},
 		{"devel bd56cb90a72e6725e", funcSymNameGo120},
 		{"go1.21", funcSymNameGo120},
-		{"unkown version", funcSymNameGo120},
+		{"unknown version", funcSymNameGo120},
 	} {
 		if got := FuncSymName(test.v); got != test.want {
 			t.Errorf("got %s; want %s", got, test.want)