Add extension ".bkp" as temp file

src/info/filetype.rs

@@ -87,7 +87,7 @@ impl FileExtensions {
     fn is_temp(&self, file: &File<'_>) -> bool {
         file.name.ends_with('~')
             || (file.name.starts_with('#') && file.name.ends_with('#'))
-            || file.extension_is_one_of( &[ "tmp", "swp", "swo", "swn", "bak", "bk" ])
+            || file.extension_is_one_of( &[ "tmp", "swp", "swo", "swn", "bak", "bkp", "bk" ])
     }
 
     fn is_compiled(&self, file: &File<'_>) -> bool {