Rollup merge of rust-lang#26695 - rutsky:patch-2, r=Manishearth

 r? @steveklabnik

Author: Manishearth

src/doc/trpl/the-stack-and-the-heap.md

@@ -176,7 +176,7 @@ After `bar()` is over, its frame is deallocated, leaving just `foo()` and
 | 1       | a    | 5     |
 | 0       | x    | 42    |
 
-And then `foo()` ends, leaving just `main()`
+And then `foo()` ends, leaving just `main()`:
 
 | Address | Name | Value |
 |---------|------|-------|
@@ -537,7 +537,7 @@ Generally, you should prefer stack allocation, and so, Rust stack-allocates by
 default. The LIFO model of the stack is simpler, at a fundamental level. This
 has two big impacts: runtime efficiency and semantic impact.
 
-## Runtime Efficiency.
+## Runtime Efficiency
 
 Managing the memory for the stack is trivial: The machine just
 increments or decrements a single value, the so-called “stack pointer”.