Improve wording of missing page error message (#163)

Co-authored-by: Matthew Peveler <[email protected]>

Author: CleanMachine1

.flake8

@@ -1,2 +1,2 @@
 [flake8]
-max-line-length=88
+max-line-length=88

tests/test_tldr.py

@@ -27,7 +27,7 @@ def test_error_message():
     with mock.patch("sys.argv", ["tldr", "73eb6f19cd6f"]):
         with pytest.raises(SystemExit) as pytest_wrapped_e:
             tldr.main()
-        correct_output = "`73eb6f19cd6f` documentation is not available. Consider contributing Pull Request to https://github.com/tldr-pages/tldr"  # noqa
+        correct_output = "`73eb6f19cd6f` documentation is not available.\nIf you want to contribute it, feel free to send a pull request to: https://github.com/tldr-pages/tldr" # noqa
         print("Test {}".format(pytest_wrapped_e))
         assert pytest_wrapped_e.type == SystemExit
         assert str(pytest_wrapped_e.value) == correct_output

tldr.py

@@ -467,9 +467,9 @@ def main():
             )
             if not result:
                 sys.exit((
-                    "`{cmd}` documentation is not available. "
-                    "Consider contributing Pull Request to "
-                    "https://github.com/tldr-pages/tldr"
+                    "`{cmd}` documentation is not available.\n"
+                    "If you want to contribute it, feel free to"
+                    " send a pull request to: https://github.com/tldr-pages/tldr"
                 ).format(cmd=command))
             else:
                 output(result)