Fitting 79-character-long code lines without scrollbars

[anntzer]

Currently, using default settings, the page width and font size of code samples are such that lines of code longer than 65 lines require a horizontal scrollbar (when the font used for rendering is DejaVu Sans Mono, which is likely quite common on Linux).

This seems a bit short; it would be nice if lines no longer than the PEP8 79-character limit could be displayed without a scrollbar. This is particularly relevant for sphinx plugins that directly generate pages from a bunch of actual .py files (for showcasing runnable examples), e.g. https://sphinx-gallery.readthedocs.io/.

This can be fixed either by slightly bumping up the page width, or by decreasing the code sample font size. I have a mild preference for the second option, because as of now, the code sample glyphs are clearly bigger than the running text glyphs (see example above -- the running text font is Liberation Serif), whereas I would think that the code glyphs should have the same size or if anything be slightly smaller than the running text glyphs. (I know there is an option to do this; this issue is a suggestion to change its default value.)