Update doc/specs/stdlib_math.md

Co-authored-by: Jeremie Vandenplas <[email protected]>

Author: ejovo13

doc/specs/stdlib_math.md

@@ -147,7 +147,7 @@ end program demo_linspace_complex
 
 ##### Example 2:
 
-Here inputs are of type `integer` and kind `int16`, with the result defaulting to double precision real.
+Here inputs are of type `integer` and kind `int16`, with the result defaulting to `real(dp)`.
 ```fortran
 program demo_linspace_int16
   use stdlib_math, only: linspace