Proper indentation and readability (#23082)

Included one of the C code snippets inside ```c``` to improve readability

guide/english/c/math/index.md

@@ -119,7 +119,7 @@ double angle = cos(90.00); // Givs us 0.00
 int result = sqrt(16); // Gives us 4
 double result = log(10.00) // Gives us 2.30 (note this is ln(10), not log base 10)
 ```
-
+```c
 // C code to illustrate 
 // the use of ceil function. 
 #include <stdio.h> 
@@ -141,7 +141,7 @@ printf ("value4 = %.1lf\n", ceil(val4));
       
   return(0); 
 } 
-
+```
 # Before you go on...
 ## A review
 * There are several basic operators: