fix dupe word typos (#490)

src/print.rs

@@ -135,7 +135,7 @@ impl BacktraceFrameFmt<'_, '_, '_> {
             symbol.name(),
             // TODO: this isn't great that we don't end up printing anything
             // with non-utf8 filenames. Thankfully almost everything is utf8 so
-            // this shouldn't be too too bad.
+            // this shouldn't be too bad.
             symbol
                 .filename()
                 .and_then(|p| Some(BytesOrWideString::Bytes(p.to_str()?.as_bytes()))),

src/symbolize/gimli/libs_macos.rs

@@ -113,8 +113,8 @@ fn native_library(i: u32) -> Option<Library> {
     // file offset 0 with a nonzero size. For whatever reason when this
     // is present it appears to mean that the symbol table is relative
     // to just the vmaddr slide for the library. If it's *not* present
-    // then the symbol table is relative to the the vmaddr slide plus
-    // the segment's stated address.
+    // then the symbol table is relative to the vmaddr slide plus the
+    // segment's stated address.
     //
     // To handle this situation if we *don't* find a text section at
     // file offset zero then we increase the bias by the first text

src/symbolize/gimli/macho.rs

@@ -13,7 +13,7 @@ type MachSection = <Mach as MachHeader>::Section;
 type MachNlist = <Mach as MachHeader>::Nlist;
 
 impl Mapping {
-    // The loading path for OSX is is so different we just have a completely
+    // The loading path for OSX is so different we just have a completely
     // different implementation of the function here. On OSX we need to go
     // probing the filesystem for a bunch of files.
     pub fn new(path: &Path) -> Option<Mapping> {