Fix small typo in reference/profiles.md

Author: louib

src/doc/src/reference/profiles.md

@@ -158,7 +158,7 @@ dependencies will also be forced to built with the `unwind` strategy.
 
 The `incremental` setting controls the [`-C incremental` flag] which controls
 whether or not incremental compilation is enabled. Incremental compilation
-causes `rustc` to to save additional information to disk which will be reused
+causes `rustc` to save additional information to disk which will be reused
 when recompiling the crate, improving re-compile times. The additional
 information is stored in the `target` directory.