[layout] Make "small" line spacing equal to normal spacing.

Now "normal" is 10pt/12pt (as it has always been) and "small" is
9pt/12pt. This makes notes and examples use the same line spacing as
the ambient text.

Author: tkoeppe

source/layout.tex

@@ -29,6 +29,12 @@
 %% than immediately following the main text.
 \feetatbottom
 
+%%--------------------------------------------------
+%% Make the "small" size, used for notes and examples, have the same
+%% line height as the normal text.
+\renewcommand{\normalsize}{\fontsize{10pt}{12pt}\selectfont}
+\renewcommand{\small}{\fontsize{9pt}{12pt}\selectfont}
+
 %%--------------------------------------------------
 %% Paragraph and bullet numbering