refactor: change method name

src/chain.rs

@@ -140,7 +140,7 @@ impl Certificate {
         Ok(result)
     }
 
-    pub fn to_plain(&self) -> Result<String, ()> {
+    pub fn to_pem(&self) -> Result<String, ()> {
         match self.cert.to_pem() {
             Ok(pem) => String::from_utf8(pem).map_err(|_| ()),
             Err(_) => Err(()),

src/main.rs

@@ -131,7 +131,7 @@ fn main() -> Result<(), ()> {
                     return Err(());
                 }
                 for cert in chain.certs() {
-                    match cert.to_plain() {
+                    match cert.to_pem() {
                         Ok(plain) => print!("{}", plain),
                         Err(_) => {
                             eprintln!(