refact(core): change backtrace syntax

Author: StunxFS

lib/core/src/backtrace.c.ri

@@ -53,7 +53,7 @@ func bt_print_callback(
         } else {
             string.from_raw(filename_ptr)
         };
-        console_eprintln("   at {} ({}:{})", fn_name, file_name, lineno);
+        console_eprintln("   at {} from \"{}\":{}", fn_name, file_name, lineno);
     }
     return 0;
 }

lib/core/src/errors.c.ri

@@ -70,8 +70,8 @@ struct ReturnTrace {
     func print(self) {
         for trace in self.traces {
             console_eprintln(
-                "   at {} ({}:{})", demangle_symbol(trace.name), trace.file,
-                trace.line
+                "   at {} from \"{}\":{}", demangle_symbol(trace.name),
+                trace.file, trace.line
             );
         }
     }

lib/core/src/string.c.ri

@@ -7,7 +7,7 @@ import c/libc;
 static emptyString = string(c"", 0, true);
 
 #[boxed]
-public struct string < Stringable, Hashable {
+public struct string < Stringable, Hashable, Throwable {
     public ptr: [&]uint8;
     public len: usize;
     is_ref: bool;