Propagate tech review edits to appendices to src

src/appendix-01-keywords.md

@@ -15,18 +15,17 @@ The following is a list of keywords currently in use, with their functionality
 described.
 
 * `as` - perform primitive casting, disambiguate the specific trait containing
-  an item, or rename items in `use` and `extern crate` statements
+  an item, or rename items in `use` statements
 * `async` -  return a `Future` instead of blocking the current thread
 * `await` - suspend execution until the result of a `Future` is ready
 * `break` - exit a loop immediately
 * `const` - define constant items or constant raw pointers
 * `continue` - continue to the next loop iteration
-* `crate` - link an external crate or a macro variable representing the crate in
-  which the macro is defined
+* `crate` - in a module path, refers to the crate root
 * `dyn` - dynamic dispatch to a trait object
 * `else` - fallback for `if` and `if let` control flow constructs
 * `enum` - define an enumeration
-* `extern` - link an external crate, function, or variable
+* `extern` - link an external function or variable
 * `false` - Boolean false literal
 * `fn` - define a function or the function pointer type
 * `for` - loop over items from an iterator, implement a trait, or specify a
@@ -51,7 +50,8 @@ described.
 * `trait` - define a trait
 * `true` - Boolean true literal
 * `type` - define a type alias or associated type
-* `union` - define a [union] and is only a keyword when used in a union declaration
+* `union` - define a [union][union]<!-- ignore -->; is only a keyword when used
+  in a union declaration
 * `unsafe` - denote unsafe code, functions, traits, or implementations
 * `use` - bring symbols into scope
 * `where` - denote clauses that constrain a type
@@ -124,9 +124,11 @@ This code will compile without any errors. Note the `r#` prefix on the function
 name in its definition as well as where the function is called in `main`.
 
 Raw identifiers allow you to use any word you choose as an identifier, even if
-that word happens to be a reserved keyword. In addition, raw identifiers allow
-you to use libraries written in a different Rust edition than your crate uses.
-For example, `try` isn’t a keyword in the 2015 edition but is in the 2018
+that word happens to be a reserved keyword. This gives us more freedom to
+choose identifier names, as well as lets us integrate with programs written in
+a language where these words aren’t keywords. In addition, raw identifiers
+allow you to use libraries written in a different Rust edition than your crate
+uses. For example, `try` isn’t a keyword in the 2015 edition but is in the 2018
 edition. If you depend on a library that’s written using the 2015 edition and
 has a `try` function, you’ll need to use the raw identifier syntax, `r#try` in
 this case, to call that function from your 2018 edition code. See [Appendix

src/appendix-04-useful-development-tools.md

@@ -32,8 +32,8 @@ on `rustfmt`, see [its documentation][rustfmt].
 ### Fix Your Code with `rustfix`
 
 The rustfix tool is included with Rust installations and can automatically fix
-compiler warnings that have one way to correct the problem that’s likely what
-you want. It’s likely you’ve seen compiler warnings before. For example,
+compiler warnings that have a clear way to correct the problem that’s likely
+what you want. It’s likely you’ve seen compiler warnings before. For example,
 consider this code:
 
 <span class="filename">Filename: src/main.rs</span>