small fix ch04-03 & code block typo ch07-02

src/ch04-03-slices.md

@@ -158,7 +158,7 @@ in the slice and `ending_index` is one more than the last position in the
 slice. Internally, the slice data structure stores the starting position and
 the length of the slice, which corresponds to `ending_index` minus
 `starting_index`. So in the case of `let world = &s[6..11];`, `world` would be
-a slice that contains a pointer to the 7th byte of `s` with a length value of 5.
+a slice that contains a pointer to the 7th byte (counting from 1) of `s` with a length value of 5.
 
 Figure 4-6 shows this in a diagram.
 

src/ch07-02-defining-modules-to-control-scope-and-privacy.md

@@ -29,7 +29,7 @@ Listing 7-1 into *src/lib.rs* to define some modules and function signatures.
 
 <span class="filename">Filename: src/lib.rs</span>
 
-```rust
+```rust,ignore
 mod front_of_house {
     mod hosting {
         fn add_to_waitlist() {}