Fix some mixed types in asm.md.

This commit fixes some instances where return types did not match the type of
the variable being returned or printf format strings did not match the types of
arguments.

Theory/asm.md

@@ -307,7 +307,7 @@ a = 100
 Or for example the `I` constraint which represents a `32-bit` integer. The difference between the `i` and `I` constraints is that `i` is more general, while `I` is for strictly `32-bit` integer data. For example if you try to compile the following example:
 
 ```C
-int test_asm(int nr)
+unsigned long test_asm(int nr)
 {
         unsigned long a = 0;
 
@@ -330,7 +330,7 @@ test.c:7:9: error: impossible constraint in ‘asm’
 when:
 
 ```C
-int test_asm(int nr)
+unsigned long test_asm(int nr)
 {
         unsigned long a = 0;
 
@@ -358,7 +358,7 @@ int main(void)
         static unsigned long element;
         
         __asm__ volatile("movq 16+%1, %0" : "=r"(element) : "o"(arr));
-        printf("%d\n", element);
+        printf("%lu\n", element);
         return 0;
 }
 ```

contributors.md

@@ -85,3 +85,4 @@ Thank you to all contributors:
 * [Piyush Pangtey](https://github.com/pangteypiyush)
 * [Alfred Agrell](https://github.com/Alcaro)
 * [Jakub Wilk](https://github.com/jwilk)
+* [Matthew Fernandez](https://github.com/Smattr)