fix(program_units_and_procedures): drop explicit anchor

In this test, the explicit anchor `modules` (lower case) is
dropped.  Does this yield a functional link across the files?

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

Author: nbehrnd

source/learn/f95_features/program_units_and_procedures.md

@@ -77,7 +77,7 @@ names of implied-DO variables have a scope of the statement that
 contains them.
 
 
-## Modules {#modules}
+## Modules
 
 Modules are used to package
 
@@ -201,7 +201,7 @@ Also, `inout` is possible: here the actual argument must be a variable
 Arguments may be optional:
 
 ```f90
-subroutine mincon(n, f, x, upper, lower, equalities, inequalities, & 
+subroutine mincon(n, f, x, upper, lower, equalities, inequalities, &
   convex, xstart)
   real, optional, dimension :: upper, lower
   :