Merge pull request #4260 from drvoss/patch-68

Update cpp-type-system-modern-cpp.md

Author: colin-home

docs/cpp/cpp-type-system-modern-cpp.md

@@ -80,7 +80,7 @@ Any built-in or user-defined type may be qualified by the const keyword. Additio
 ```cpp
 
 const double PI = 3.1415;
-PI = .75 //Error. Cannot modify const variable.
+PI = .75; //Error. Cannot modify const variable.
 ```
 
 The **`const`** qualifier is used extensively in function and variable declarations and "const correctness" is an important concept in C++; essentially it means to use **`const`** to guarantee, at compile time, that values are not modified unintentionally. For more information, see [`const`](../cpp/const-cpp.md).