Various minor/cosmetic improvements to code

src/librustc_codegen_llvm/debuginfo/utils.rs

@@ -26,7 +26,7 @@ use syntax_pos::{self, Span};
 pub fn is_node_local_to_unit(cx: &CodegenCx, def_id: DefId) -> bool
 {
     // The is_local_to_unit flag indicates whether a function is local to the
-    // current compilation unit (i.e. if it is *static* in the C-sense). The
+    // current compilation unit (i.e., if it is *static* in the C-sense). The
     // *reachable* set should provide a good approximation of this, as it
     // contains everything that might leak out of the current crate (by being
     // externally visible or by being inlined into something externally