errors: rewrite errors to follow go best practices

Errors should not start capitalised and they should not contain the word error
or state that they "failed" as we already know it is an error

Signed-off-by: Kristoffer Dalby <kristoffer@dalby.cc>

hscontrol/noise.go

@@ -79,7 +79,7 @@ func (h *Headscale) NoiseUpgradeHandler(
 		noiseServer.earlyNoise,
 	)
 	if err != nil {
-		httpError(writer, fmt.Errorf("noise upgrade failed: %w", err))
+		httpError(writer, fmt.Errorf("upgrading noise connection: %w", err))
 		return
 	}