.github,whois,dns manager: assorted typos in messages and markdown

Updates #cleanup
Updates #engdocs
Updates 7f5932e

Signed-off-by: hdhoang <code@hdhoang.space>

.github/CONTRIBUTING.md

@@ -14,4 +14,4 @@ Please squash your code review edits & force push. Multiple commits in
 a PR are fine, but only if they're each logically separate and all tests pass
 at each stage. No fixup commits.
 
-See [commit-messages.md](docs/commit-messages.md) (or skim `git log`) for our commit message style.
+See [commit-messages.md](../docs/commit-messages.md) (or skim `git log`) for our commit message style.

cmd/tailscale/cli/whois.go

@@ -26,7 +26,7 @@ var whoisCmd = &ffcli.Command{
 	FlagSet: func() *flag.FlagSet {
 		fs := newFlagSet("whois")
 		fs.BoolVar(&whoIsArgs.json, "json", false, "output in JSON format")
-		fs.StringVar(&whoIsArgs.proto, "proto", "", `protocol; one of "tcp" or "udp"; empty mans both `)
+		fs.StringVar(&whoIsArgs.proto, "proto", "", `protocol; one of "tcp" or "udp"; empty means both`)
 		return fs
 	}(),
 }

net/dns/manager_linux.go

@@ -372,7 +372,7 @@ func resolvedIsActuallyResolver(logf logger.Logf, env newOSConfigEnv, dbg func(k
 func isLibnssResolveUsed(env newOSConfigEnv) error {
 	bs, err := env.fs.ReadFile("/etc/nsswitch.conf")
 	if err != nil {
-		return fmt.Errorf("reading /etc/resolv.conf: %w", err)
+		return fmt.Errorf("reading /etc/nsswitch.conf: %w", err)
 	}
 	for _, line := range strings.Split(string(bs), "\n") {
 		fields := strings.Fields(line)