en: music-and-technology-synthesis-simple-melodies: Fix typos

* src/en/sections/music-and-technology-synthesis-simple-melodies.tex: Fix some
typos.

src/en/sections/music-and-technology-synthesis-simple-melodies.tex

@@ -108,8 +108,8 @@ \section{Programming of simple melodies}
 
 The names of the constants are usually written in capital letters, so it would
 be more correct to write those constants as ``C4'', ``D4'', ``E4'' and so on.
-But we are using regular letters here to avoid naming conflict wit the constants
-that are already defined in the Arduino (e.g. ``A4''.)
+But we are using regular letters here to avoid naming conflicts with the
+constants that are already defined in the Arduino (e.g. ``A4''.)
 
 Currently we need only the notes from the fourth octave.  It is reasonable to
 define those constants before \texttt{setup} procedure.