Update doc/specs/stdlib_specialfunctions.md

Co-authored-by: Sebastian Ehlert <[email protected]>

Author: hsnyder

doc/specs/stdlib_specialfunctions.md

@@ -21,7 +21,7 @@ This is an `elemental` function.
 
 ### Syntax
 
-`result = [[stdlib_specialfunctions(module):legendre(interface)]](n, x)`
+`result = [[stdlib_specialfunctions(module):legendre(interface)]] (n, x)`
 
 ### Arguments