fix format logical

Author: Vandenplas, Jeremie

example/strings/example_ends_with.f90

@@ -1,6 +1,6 @@
 program example_ends_with
   use stdlib_strings, only: ends_with
   implicit none
-  print'(l)', ends_with("pattern", "ern")  ! T
-  print'(l)', ends_with("pattern", "pat")  ! F
+  print'(l1)', ends_with("pattern", "ern")  ! T
+  print'(l1)', ends_with("pattern", "pat")  ! F
 end program example_ends_with

example/strings/example_starts_with.f90

@@ -1,6 +1,6 @@
 program example_starts_with
   use stdlib_strings, only: starts_with
   implicit none
-  print'(l)', starts_with("pattern", "pat")  ! T
-  print'(l)', starts_with("pattern", "ern")  ! F
+  print'(l1)', starts_with("pattern", "pat")  ! T
+  print'(l1)', starts_with("pattern", "ern")  ! F
 end program example_starts_with