Document repeated use of -t, fix clippy warnings

spamassassin-milter.8

@@ -159,6 +159,7 @@ must be a comma-separated list of IP network addresses, for example,
 If
 .I NETS
 is empty, no IP addresses are trusted.
+This option may be given multiple times.
 If this option is not used, all connections from loopback addresses are trusted.
 .TP
 .BR \-v ", " \-\-verbose

src/config.rs

@@ -265,8 +265,8 @@ mod tests {
     #[test]
     fn spamc_args_extends_args() {
         let config = Config::builder()
-            .spamc_args(&["-p", "3030"])
-            .spamc_args(&["-x"])
+            .spamc_args(["-p", "3030"])
+            .spamc_args(["-x"])
             .build();
 
         assert_eq!(

tests/common/mod.rs

@@ -26,7 +26,7 @@ pub fn configure_spamc(builder: ConfigBuilder) -> ConfigBuilder {
     // Note: Must use `-F` instead of `--config` due to a bug in `spamc`.
     // `--no-safe-fallback` prevents connection attempts from failing silently,
     // and `--log-to-stderr` avoids polluting syslog with test output.
-    builder.spamc_args(&["-F", "/dev/null", "--no-safe-fallback", "--log-to-stderr"])
+    builder.spamc_args(["-F", "/dev/null", "--no-safe-fallback", "--log-to-stderr"])
 }
 
 pub const SPAMD_PORT: u16 = 3783;  // mock port