Update doc/specs/stdlib_str2num.md

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

Author: jalvesz

doc/specs/stdlib_str2num.md

@@ -30,7 +30,7 @@ Convert a string or an array of strings to numerical types.
 
 ### Return value
 
-Return a scalar of numerical type (`integer`, `real32` or `real64`).
+Return a scalar of numerical type (i.e., `integer`, or `real`).
 
 ### Example