Simplify signal handling code.

This does not require `//go:build`.

src/signal.go

@@ -1,4 +1,6 @@
-//go:build unix
+// See https://pkg.go.dev/os/signal#hdr-Windows for a description of what this module
+// will do on Windows (tl;dr nothing calls the reload handler, the interrupt handler works
+// more or less how you'd expect).
 
 package git_pages
 
@@ -21,7 +23,7 @@ func OnReload(handler func()) {
 
 func WaitForInterrupt() {
 	sigint := make(chan os.Signal, 1)
-	signal.Notify(sigint, syscall.SIGINT)
+	signal.Notify(sigint, syscall.SIGINT, syscall.SIGTERM)
 	<-sigint
 	signal.Stop(sigint)
 }

src/signal_other.go

@@ -1,13 +0,0 @@
-//go:build !unix
-
-package git_pages
-
-func OnReload(handler func()) {
-	// not implemented
-}
-
-func WaitForInterrupt() {
-	for {
-		// Ctrl+C not supported
-	}
-}