I am relatively new to Plain TEX and I wanted to define a
\section command to typeset a bold and centered text with some spacing around it.
Here is what I came up with.
Is that a correct way to do so? In particular I don't know if
\medskip has to be typed before or after
\nobreak. I know that the
\beginsection macro (that left aligns the section title) is more complex than that but I don't understand what benefits it has.