Small wording changes

Author: Mike Krisher

src/ch10-03-lifetime-syntax.md

@@ -8,13 +8,13 @@ One detail we didn’t discuss in the [“References and
 Borrowing”][references-and-borrowing]<!-- ignore --> section in Chapter 4 is
 that every reference in Rust has a *lifetime*, which is the scope for which
 that reference is valid. Most of the time, lifetimes are implicit and inferred,
-just like most of the time, types are inferred. We only must annotate types
+just like most of the time, types are inferred. We must only annotate types
 when multiple types are possible. In a similar way, we must annotate lifetimes
 when the lifetimes of references could be related in a few different ways. Rust
 requires us to annotate the relationships using generic lifetime parameters to
 ensure the actual references used at runtime will definitely be valid.
 
-Annotating lifetimes is not even a concept most other programming languages
+Annotating lifetimes is not a concept most other programming languages
 have, so this is going to feel unfamiliar. Although we won’t cover lifetimes in
 their entirety in this chapter, we’ll discuss common ways you might encounter
 lifetime syntax so you can get comfortable with the concept.