Correct wording, category for starter conversion (#235)

- Now a flowchart (and a renamed label)
- More explicit wording as per
https://github.com/hendricius/the-sourdough-framework/issues/234

book/sourdough-starter/sourdough-starter-types.tex

@@ -122,7 +122,7 @@ starter's flavor by changing the type to a liquid starter.
 \end{figure}
 
 
-\begin{figure}[!htb]
+\begin{flowchart}[!htb]
 \begin{center}
   \input{figures/fig-liquid-starter-conversion.tex}
   \caption[Converting to a liquid starter]{The process to convert your regular
@@ -133,9 +133,9 @@ starter's flavor by changing the type to a liquid starter.
       select anaerobic microorganisms. This boosts bacteria that create lactic
       acid rather than acetic acid. The resulting acidity will be perceived as
       milder.}%
-  \label{fig:liquid-starter-conversion}
+  \label{flc:liquid-starter-conversion}
 \end{center}
-\end{figure}
+\end{flowchart}
 
 The liquid starter is made at a hydration of around \qty{500}{\percent}. This means
 the starter has much more water than flour. The additional layer of water on
@@ -193,7 +193,7 @@ times to make lacto-fermented hot sauces.
   \caption[Stiff starter upside-down]{A stiff sourdough starter that I~used to
       make a Stollen dough for Christmas. Note the bubbles on the edge of the
       container. The dough does not fall out of the jar.}%
-  \label{fig:stiff-sourdough-starter}
+  \label{flc:stiff-sourdough-starter}
 \end{figure}
 
 The stiff starter is the driest of all the starters. It has a hydration of
@@ -220,7 +220,7 @@ for a visual example of the starter's required hydration level.
   \label{fig:stiff-starter-dry-check}
 \end{figure}
 
-\begin{figure}[!htb]
+\begin{flowchart}[!htb]
 \begin{center}
   \input{figures/fig-stiff-starter-conversion.tex}
   \caption[Converting to a stiff starter]{The process to convert your regular
@@ -232,7 +232,7 @@ for a visual example of the starter's required hydration level.
       stiff consider increasing this to \qty{60}{\percent}.}%
   \label{fig:stiff-starter-conversion}
 \end{center}
-\end{figure}
+\end{flowchart}
 
 In the stiffer environment the yeast thrives more. This means you will have
 more \ch{CO2} production and less acid production. In my tests this is a game