Remove empty lines at start and end of code block

Author: Rageking8

docs/code-quality/c6393.md

@@ -26,7 +26,6 @@ Code analysis name: `LEAP_YEAR_INVALID_DATE_KEYED_LOOKUP`
 The following code creates a lookup table for the day of the year, assuming 365 days per year. However, this doesn't work if the year is a leap year:
 
 ```cpp
- 
 #include <vector> 
 
 void foo(int year) 

docs/cpp/functions-cpp.md

@@ -77,7 +77,6 @@ Optional parts of a function declaration are:
     ```cpp
     //Declare printf with C linkage.
     extern "C" int printf( const char *fmt, ... );
-
     ```
 
    For more information, see [Translation units and linkage](../cpp/program-and-linkage-cpp.md).

docs/porting/visual-cpp-what-s-new-2003-through-2015.md

@@ -226,7 +226,6 @@ Although these differences can affect your source code or other build artifacts,
    ```cpp
     error C3688: invalid literal suffix '_x'; literal operator or literal operator template 'operator ""_x' not found
     note: Did you forget a space between the string literal and the prefix of the following string literal?
-
    ```
 
    To fix this problem, add a space between the string literal and the macro.