fix(pointers.md): correct syntax of a referer

Signed-off-by: Norwid Behrnd <[email protected]>

Author: nbehrnd

source/learn/f95_features/pointers.md

@@ -13,7 +13,8 @@ They are conceptually a descriptor listing the attributes of the objects
 (targets) that the pointer may point to, and the address, if any, of a
 target. They have no associated storage until it is allocated or
 otherwise associated (by pointer assignment, see
-[Pointers in expressions and assignments](pointers_in_expressions_and_assignments)):
+[Pointers in expressions and assignments](pointers-in-expressions-and-assignments)
+below):
 
 ```f90
 allocate (var)