Update nostarch file codeblocks to match src

nostarch/chapter05.md

@@ -88,7 +88,7 @@ fn area(length: u32, width: u32) -> u32 {
 
 Let’s try running this program with `cargo run`:
 
-```bash
+```text
 The area of the rectangle is 1500 square pixels.
 ```
 
@@ -222,7 +222,7 @@ fn main() {
 
 If we run this, we get an error with this core message:
 
-```bash
+```text
 error[E0277]: the trait bound `Rectangle: std::fmt::Display` is not satisfied
 ```
 
@@ -238,7 +238,7 @@ want and structs do not have a provided implementation of `Display`.
 
 If we keep reading the errors, though, we’ll find this helpful note:
 
-```bash
+```text
 note: `Rectangle` cannot be formatted with the default formatter; try using
 `:?` instead if you are using a format string
 ```
@@ -252,13 +252,13 @@ code.
 
 Let’s try running with this change and… drat. We still get an error:
 
-```bash
+```text
 error: the trait bound `Rectangle: std::fmt::Debug` is not satisfied
 ```
 
 Again, though, the compiler has given us a helpful note!
 
-```bash
+```text
 note: `Rectangle` cannot be formatted using `:?`; if it is defined in your
 crate, add `#[derive(Debug)]` or manually implement it
 ```
@@ -285,7 +285,7 @@ fn main() {
 At this point, if we run this program, we won’t get any errors and we’ll see
 the following output:
 
-```bash
+```text
 rect1 is Rectangle { length: 50, width: 30 }
 ```
 
@@ -441,7 +441,7 @@ fn main() {
 We want to see this output, since both of `rect2`’s dimensions are smaller than
 `rect1`’s, but `rect3` is wider than `rect1`:
 
-```bash
+```text
 Can rect1 hold rect2? true
 Can rect1 hold rect3? false
 ```