added escaped comma \, to doc of breakbefore and breadafter

To sync with fvextra doc starting from v1.5.
gpoore/fvextra@16de52d (breakbefore and breakafter now support the
escaped comma \, (closes issue 15), 2022-11-10)

latex/minted/minted.dtx

@@ -951,7 +951,7 @@
 %   \item[breakafter (string) (\meta{none})]
 %     Break lines after specified characters, not just at spaces, when \texttt{breaklines=true}.
 %
-% For example, \texttt{breakafter=-/} would allow breaks after any hyphens or slashes.  Special characters given to \texttt{breakafter} should be backslash-escaped (usually \texttt{\hashchar}, \texttt{\{}, \texttt{\}}, \texttt{\%}, \texttt{[}, \texttt{]}; the backslash \texttt{\textbackslash} may be obtained via \texttt{\textbackslash\textbackslash}).
+% For example, \texttt{breakafter=-/} would allow breaks after any hyphens or slashes.  Special characters given to \texttt{breakafter} should be backslash-escaped (usually \texttt{\hashchar}, \texttt{\{}, \texttt{\}}, \texttt{\%}, \texttt{[}, \texttt{]}, and the comma \texttt{,}; the backslash \texttt{\textbackslash} may be obtained via \texttt{\textbackslash\textbackslash}).
 %
 % For an alternative, see \texttt{breakbefore}.  When \texttt{breakbefore} and \texttt{breakafter} are used for the same character, \texttt{breakbeforeinrun} and \texttt{breakafterinrun} must both have the same setting.
 %
@@ -1004,7 +1004,7 @@
 %   \item[breakbefore (string) (\meta{none})]
 %     Break lines before specified characters, not just at spaces, when \texttt{breaklines=true}.
 %
-% For example, \texttt{breakbefore=A} would allow breaks before capital A's.  Special characters given to \texttt{breakbefore} should be backslash-escaped (usually \texttt{\hashchar}, \texttt{\{}, \texttt{\}}, \texttt{\%}, \texttt{[}, \texttt{]}; the backslash \texttt{\textbackslash} may be obtained via \texttt{\textbackslash\textbackslash}).
+% For example, \texttt{breakbefore=A} would allow breaks before capital A's.  Special characters given to \texttt{breakbefore} should be backslash-escaped (usually \texttt{\hashchar}, \texttt{\{}, \texttt{\}}, \texttt{\%}, \texttt{[}, \texttt{]}, and the comma \texttt{,}; the backslash \texttt{\textbackslash} may be obtained via \texttt{\textbackslash\textbackslash}).
 %
 %  For an alternative, see \texttt{breakafter}.  When \texttt{breakbefore} and \texttt{breakafter} are used for the same character, \texttt{breakbeforeinrun} and \texttt{breakafterinrun} must both have the same setting.
 %