Fix typo in updating guide: 'phase' -> 'faze'.

site/guide/01-upgrading.md

@@ -17,11 +17,10 @@ developers wishing to migrate their applications to Rocket v0.5.
 ! note Don't panic!
 
   Simply upgrading Rocket's version string to the `0.5` series will result in
-  _many_ `rustc` compiler errors. But don't let this phase you! The vast
-  majority of changes are simple renames and `#[async_trait]` attributions which
-  manifest in a cascading of errors. As such, resolving _one_ top-level issue,
-  typically requiring minimal, trivial changes, often resolves _many_ errors in
-  one go.
+  _many_ `rustc` compiler errors. But don't let this faze you! The vast majority
+  of changes are simple renames and `#[async_trait]` attributions which manifest
+  in a cascading of errors. As such, resolving _one_ top-level issue, typically
+  requiring minimal, trivial changes, often resolves _many_ errors in one go.
 
 ## Crate Organization