[DEV-7084] TAMER: From<B, &I> for XmloReader

This serves as a constructor for the time being, decoupling from POC.  We
may do something better once we have a better idea of how the various
abstractions around this will evolve.

tamer/src/ld/poc.rs

@@ -140,7 +140,7 @@ fn load_xmlo<'a, 'i, I: Interner<'i>>(
 
     let file = fs::File::open(&path)?;
     let reader = BufReader::new(file);
-    let mut xmlo = XmloReader::new(reader, interner);
+    let mut xmlo: XmloReader<'_, _, _> = (reader, interner).into();
     let mut elig = None;
 
     let mut name: Option<&'i Symbol<'i>> = None;

tamer/src/obj/xmlo/reader.rs

@@ -684,6 +684,16 @@ impl<'i, B: BufRead, I: Interner<'i>> XmloReader<'i, B, I> {
     }
 }
 
+impl<'i, B, I> From<(B, &'i I)> for XmloReader<'i, B, I>
+where
+    B: BufRead,
+    I: Interner<'i>,
+{
+    fn from(args: (B, &'i I)) -> Self {
+        Self::new(args.0, args.1)
+    }
+}
+
 /// `xmlo` reader events.
 ///
 /// All data are parsed rather than being returned as [`u8`] slices,