How to remove dot in tabular rule when using hhline?

this adds a ; which is like : but different.

\documentclass{article}
\usepackage{hhline,colortbl}

\makeatletter
\AtBeginDocument{%
\def\HH@loop{%
  \ifx\@tempb`\def\next##1{\the\toks@\cr}\else\let\next\HH@let
  \ifx\@tempb|\if@tempswa
          \ifx\CT@drsc@\relax
           \HH@add{\hskip\doublerulesep}%
          \else
           \HH@add{{\CT@drsc@\vrule\@width\doublerulesep}}%
           \fi
          \fi\@tempswatrue
          \HH@add{{\CT@arc@\vline}}\else
  \ifx\@tempb:\if@tempswa
          \ifx\CT@drsc@\relax
           \HH@add{\hskip\doublerulesep}%
          \else
           \HH@add{{\CT@drsc@\vrule\@width\doublerulesep}}%
           \fi
              \fi\@tempswatrue
      \HH@add{\@tempc\HH@box\arrayrulewidth\arrayrulewidth\@tempc}\else
  \ifx\@tempb;\if@tempswa
          \ifx\CT@drsc@\relax
           \HH@add{\hskip\doublerulesep}%
          \else
           \HH@add{{\CT@drsc@\vrule\@width\doublerulesep}}%
           \fi
              \fi\@tempswatrue
      \HH@add{\@tempc\HH@box\z@\arrayrulewidth\@tempc}\else
  \ifx\@tempb##\if@tempswa\HH@add{\hskip\doublerulesep}\fi\@tempswatrue
         \HH@add{{\CT@arc@\vline\copy\@ne\@tempc\vline}}\else
  \ifx\@tempb~\@tempswafalse
           \if@firstamp\@firstampfalse\else\HH@add{&\omit}\fi
              \ifx\CT@drsc@\relax
                \HH@add{\hfil}\else
                 \HH@add{{%
                   \CT@drsc@\leaders\hrule\@height\HH@height\hfil}}%
               \fi
                 \else
  \ifx\@tempb-\@tempswafalse
           \gdef\HH@height{\arrayrulewidth}%
           \if@firstamp\@firstampfalse\else\HH@add{&\omit}\fi
              \HH@add{{%
                \CT@arc@\leaders\hrule\@height\arrayrulewidth\hfil}}%
                           \else
  \ifx\@tempb=\@tempswafalse
       \gdef\HH@height{\dimen\thr@@}%
       \if@firstamp\@firstampfalse\else\HH@add{&\omit}\fi
       \HH@add
          {\rlap{\copy\@ne}\leaders\copy\@ne\hfil\llap{\copy\@ne}}\else
  \ifx\@tempb t\HH@add{%
    \def\HH@height{\dimen\thr@@}%
    \HH@box\doublerulesep\z@}\@tempswafalse\else
  \ifx\@tempb b\HH@add{%
    \def\HH@height{\dimen\thr@@}%
    \HH@box\z@\doublerulesep}\@tempswafalse\else
  \ifx\@tempb>\def\next##1##2{%
     \HH@add{%
      {\baselineskip\p@\relax
       ##2%
      \global\setbox\@ne\HH@box\doublerulesep\doublerulesep}}%
       \HH@let!}\else
  \PackageWarning{hhline}%
      {\meaning\@tempb\space ignored in \noexpand\hhline argument%
       \MessageBreak}%
  \fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi
  \next}
}
\makeatother
\begin{document}
\begin{tabular}{|c||p{2.5cm}|}
\hhline{~|-}
\multicolumn{1}{c|}{} & \multicolumn{1}{c|}{\textbf{JANUARY}} \\[0.75ex]
\hhline{-;:=}
\textbf{Su} & \\[0.75ex]
\end{tabular}
\end{document}

The probelm comes from a\hhline which mixes simple and doublerule. A solution consists in making two simple \hhmines with a vertical space in-between:

\documentclass{article}
\usepackage{hhline}

\begin{document}

\begin{tabular}{|c||p{2.5cm}|}
\hhline{~|-}
\multicolumn{1}{c|}{}& {\textbf{JANUARY}} \\[0.75ex]
\hhline{~|-}\noalign{\vspace*{\doublerulesep}}
\hhline{-||-}
\textbf{Su} & \\[0.75ex]
\end{tabular}

\end{document}