Use const params

Resolves the following thread(s):
- jank-lang#763 (comment).

Author: shantanu-sardesai

compiler+runtime/include/cpp/jank/runtime/core/math.hpp

@@ -1103,8 +1103,8 @@ namespace jank::runtime
   i64 to_long(obj::nil_ref const l);
   i64 to_long(obj::integer_ref const l);
   i64 to_long(obj::real_ref const l);
-  i64 to_long(i64 l);
-  i64 to_long(f64 l);
+  i64 to_long(i64 const l);
+  i64 to_long(f64 const l);
 
   f64 to_real(object_ref const o);
 

compiler+runtime/src/cpp/jank/runtime/core/math.cpp

@@ -1013,12 +1013,12 @@ namespace jank::runtime
     return to_int(l);
   }
 
-  i64 to_long(i64 l)
+  i64 to_long(i64 const l)
   {
     return to_int(l);
   }
 
-  i64 to_long(f64 l)
+  i64 to_long(f64 const l)
   {
     return to_int(l);
   }