der, spki: rename to_owned method

The naming of the `to_owned` method was a bit unfortunate as it
triggered conflicts with the `alloc::borrow::ToOwned` method. When used,
this would make for compiler messages asking things like:
```
error[E0034]: multiple applicable items in scope
   --> certval/src/validator/name_constraints_set.rs:748:34
    |
748 |                         value: a.to_owned(),
    |                                  ^^^^^^^^ multiple `to_owned` found
    |
    = note: candidate RustCrypto#1 is defined in an impl of the trait `RefToOwned` for the type `AnyRef<'a>`
    = note: candidate RustCrypto#2 is defined in an impl of the trait `ToOwned` for the type `T`
help: disambiguate the associated function for candidate RustCrypto#1
    |
748 |                         value: RefToOwned::to_owned(&a),
    |                                ~~~~~~~~~~~~~~~~~~~~~~~~
help: disambiguate the associated function for candidate RustCrypto#2
    |
748 |                         value: ToOwned::to_owned(&a),
    |                                ~~~~~~~~~~~~~~~~~~~~~
```

der/src/asn1/any.rs

@@ -277,7 +277,7 @@ mod allocating {
 
     impl<'a> RefToOwned<'a> for AnyRef<'a> {
         type Owned = Any;
-        fn to_owned(&self) -> Self::Owned {
+        fn ref_to_owned(&self) -> Self::Owned {
             Any {
                 tag: self.tag(),
                 value: BytesOwned::from(self.value),

der/src/asn1/bit_string.rs

@@ -379,7 +379,7 @@ mod allocating {
 
     impl<'a> RefToOwned<'a> for BitStringRef<'a> {
         type Owned = BitString;
-        fn to_owned(&self) -> Self::Owned {
+        fn ref_to_owned(&self) -> Self::Owned {
             BitString {
                 unused_bits: self.unused_bits,
                 bit_length: self.bit_length,

der/src/asn1/ia5_string.rs

@@ -150,9 +150,9 @@ mod allocation {
 
     impl<'a> RefToOwned<'a> for Ia5StringRef<'a> {
         type Owned = Ia5String;
-        fn to_owned(&self) -> Self::Owned {
+        fn ref_to_owned(&self) -> Self::Owned {
             Ia5String {
-                inner: self.inner.to_owned(),
+                inner: self.inner.ref_to_owned(),
             }
         }
     }

der/src/asn1/integer/bigint.rs

@@ -277,8 +277,8 @@ mod allocating {
 
     impl<'a> RefToOwned<'a> for IntRef<'a> {
         type Owned = Int;
-        fn to_owned(&self) -> Self::Owned {
-            let inner = self.inner.to_owned();
+        fn ref_to_owned(&self) -> Self::Owned {
+            let inner = self.inner.ref_to_owned();
 
             Int { inner }
         }
@@ -384,8 +384,8 @@ mod allocating {
 
     impl<'a> RefToOwned<'a> for UintRef<'a> {
         type Owned = Uint;
-        fn to_owned(&self) -> Self::Owned {
-            let inner = self.inner.to_owned();
+        fn ref_to_owned(&self) -> Self::Owned {
+            let inner = self.inner.ref_to_owned();
 
             Uint { inner }
         }

der/src/asn1/printable_string.rs

@@ -221,9 +221,9 @@ mod allocation {
 
     impl<'a> RefToOwned<'a> for PrintableStringRef<'a> {
         type Owned = PrintableString;
-        fn to_owned(&self) -> Self::Owned {
+        fn ref_to_owned(&self) -> Self::Owned {
             PrintableString {
-                inner: self.inner.to_owned(),
+                inner: self.inner.ref_to_owned(),
             }
         }
     }

der/src/asn1/teletex_string.rs

@@ -179,9 +179,9 @@ mod allocation {
 
     impl<'a> RefToOwned<'a> for TeletexStringRef<'a> {
         type Owned = TeletexString;
-        fn to_owned(&self) -> Self::Owned {
+        fn ref_to_owned(&self) -> Self::Owned {
             TeletexString {
-                inner: self.inner.to_owned(),
+                inner: self.inner.ref_to_owned(),
             }
         }
     }

der/src/bytes_ref.rs

@@ -145,7 +145,7 @@ mod allocating {
 
     impl<'a> RefToOwned<'a> for BytesRef<'a> {
         type Owned = BytesOwned;
-        fn to_owned(&self) -> Self::Owned {
+        fn ref_to_owned(&self) -> Self::Owned {
             BytesOwned::from(*self)
         }
     }

der/src/referenced.rs

@@ -21,7 +21,7 @@ pub trait RefToOwned<'a> {
         Self: 'a;
 
     /// Creates a new object taking ownership of the data
-    fn to_owned(&self) -> Self::Owned;
+    fn ref_to_owned(&self) -> Self::Owned;
 }
 
 impl<T> OwnedToRef for Option<T>
@@ -41,7 +41,7 @@ where
     T::Owned: OwnedToRef,
 {
     type Owned = Option<T::Owned>;
-    fn to_owned(&self) -> Self::Owned {
-        self.as_ref().map(|o| o.to_owned())
+    fn ref_to_owned(&self) -> Self::Owned {
+        self.as_ref().map(|o| o.ref_to_owned())
     }
 }

der/src/str_ref.rs

@@ -85,7 +85,7 @@ mod allocating {
 
     impl<'a> RefToOwned<'a> for StrRef<'a> {
         type Owned = StrOwned;
-        fn to_owned(&self) -> Self::Owned {
+        fn ref_to_owned(&self) -> Self::Owned {
             StrOwned::from(*self)
         }
     }

spki/src/algorithm.rs

@@ -171,10 +171,10 @@ mod allocating {
 
     impl<'a> RefToOwned<'a> for AlgorithmIdentifierRef<'a> {
         type Owned = AlgorithmIdentifierOwned;
-        fn to_owned(&self) -> Self::Owned {
+        fn ref_to_owned(&self) -> Self::Owned {
             AlgorithmIdentifier {
                 oid: self.oid,
-                parameters: self.parameters.to_owned(),
+                parameters: self.parameters.ref_to_owned(),
             }
         }
     }

spki/src/spki.rs

@@ -193,10 +193,10 @@ mod allocating {
 
     impl<'a> RefToOwned<'a> for SubjectPublicKeyInfoRef<'a> {
         type Owned = SubjectPublicKeyInfoOwned;
-        fn to_owned(&self) -> Self::Owned {
+        fn ref_to_owned(&self) -> Self::Owned {
             SubjectPublicKeyInfo {
-                algorithm: self.algorithm.to_owned(),
-                subject_public_key: self.subject_public_key.to_owned(),
+                algorithm: self.algorithm.ref_to_owned(),
+                subject_public_key: self.subject_public_key.ref_to_owned(),
             }
         }
     }