docs: Fix highlighting in examples

I never noticed when we added the license and copyright information to
the top of all the source files that we didn't account for the
lines highlighted in the included examples.  This adjusts things such
that (1) we don't include all that header stuff when generating the
docs, and only include the lines of code that are really relevant to
share on the examples page, and (2) the appropriate lines are
highlighted.

doc/source/examples.rst

@@ -16,13 +16,14 @@ straightforward it is to get up and running with it.
 .. literalinclude:: ../../example/basic.py
    :language: python
    :linenos:
+   :lines: 10-
    :caption: ``example/basic.py``
-   :emphasize-lines: 5,16-19
+   :emphasize-lines: 3,14-17
 
 .. note::
 
    The only thing you're adding to your script to take advantage of
-   ``reverse_argparse`` is lines 7 and 19--22.
+   ``reverse_argparse`` is lines 3 and 14--17.
 
 Running the script, and passing an argument to it, yields the following:
 
@@ -37,8 +38,9 @@ arguments, but this time with default values.
 .. literalinclude:: ../../example/default_values.py
    :language: python
    :linenos:
+   :lines: 10-
    :caption: ``example/default_values.py``
-   :emphasize-lines: 10-11
+   :emphasize-lines: 8-9
 
 Now running the script with the same command line arguments yields:
 
@@ -54,8 +56,9 @@ will be translated to an absolute path behind the scenes.
 .. literalinclude:: ../../example/relative_references.py
    :language: python
    :linenos:
+   :lines: 10-
    :caption: ``example/relative_references.py``
-   :emphasize-lines: 3,13
+   :emphasize-lines: 1,11
 
 Now running the script and pointing to a file in your current working directory
 yields:
@@ -73,8 +76,9 @@ standard format.
 .. literalinclude:: ../../example/post_processing.py
    :language: python
    :linenos:
+   :lines: 10-
    :caption: ``example/post_processing.py``
-   :emphasize-lines: 6,16,20-21
+   :emphasize-lines: 4,14,18-19
 
 Now running the script and specifying a relative date/time yields:
 
@@ -92,8 +96,9 @@ different flags and corresponding values are.
 .. literalinclude:: ../../example/pretty_printing.py
    :language: python
    :linenos:
+   :lines: 10-
    :caption: ``example/pretty_printing.py``
-   :emphasize-lines: 28
+   :emphasize-lines: 26
 
 Now running the script and specifying a relative date/time yields:
 
@@ -114,8 +119,9 @@ shows the subtle difference.
 .. literalinclude:: ../../example/subparsers.py
    :language: python
    :linenos:
+   :lines: 10-
    :caption: ``example/subparsers.py``
-   :emphasize-lines: 11-18
+   :emphasize-lines: 9-19
 
 Running this script and using the ``foo`` subcommand yields: