Document the "L" needed for long integer literals

See processing/processing#4878

content/api_en/include/long.xml

@@ -11,16 +11,18 @@
 <example>
 <image></image>
 <code><![CDATA[
-long a;          // Declare variable 'a' of type long
-a = 23;          // Assign 'a' the value 23
-long b = -256;   // Declare variable 'b' and assign it the value -256
-long c = a + b;  // Declare variable 'c' and assign it the sum of 'a' and 'b'
-int i = (int)c;  // Converts the value of 'c' from a long to an int
+long a;           // Declare variable 'a' of type long and assign a large value:
+//a = 2147483648; // Error: The literal of type int is out of range
+a = 2147483648L;  // Instead, add an "L" to the number to mark it as a long
+
+long b = -256;    // Declare variable 'b' and assign it the value -256
+long c = a + b;   // Declare variable 'c' and assign it the sum of 'a' and 'b'
+int i = (int)c;   // Converts the value of 'c' from a long to an int
 ]]></code> 
 </example>
 
 <description><![CDATA[
-Datatype for large integers. While integers can be as large as 2,147,483,647 and as low as -2,147,483,648 (stored as 32 bits), a <b>long</b> integer has a minimum value of -9,223,372,036,854,775,808 and a maximum value of 9,223,372,036,854,775,807 (stored as 64 bits). Use this datatype when you need a number to have a greater magnitude than can be stored within an <b>int</b>. Processing functions don't use this datatype, so while they work in the language, you'll usually have to convert to a <b>int</b> using the <b>(int)</b> syntax before passing into a function.
+Datatype for large integers. While integers can be as large as 2,147,483,647 and as low as -2,147,483,648 (stored as 32 bits), a <b>long</b> integer has a minimum value of -9,223,372,036,854,775,808 and a maximum value of 9,223,372,036,854,775,807 (stored as 64 bits). Use this datatype when you need a number to have a greater magnitude than can be stored within an <b>int</b>. When assigning literal values that are larger than this magnitude, it is necessary to also append the qualifier "L" to the number, as shown in the example above. Processing functions don't use this datatype, so while they work in the language, you'll usually have to convert to a <b>int</b> using the <b>(int)</b> syntax before passing into a function.
 ]]></description>
 
 <syntax>