Move mixing seed from troubleshooting to mix-ins (#415)

This was written way before the mix-ins sections, made sense back then
but not so much anymore so moving it out.

formatted text and added centering, labels etc while at it.

book/troubleshooting/misc.tex

@@ -188,7 +188,7 @@ protecting your sourdough starter from aerobic mold entering through
 the top.
 
 \begin{figure}[!htb]
-\centering
+  \centering
   \includegraphics[width=0.5\textwidth]{sourdough-starter-hooch}
   \caption[Hooch] {Hooch building on top of a sourdough
       starter~\cite{liquid+on+starter}.}%
@@ -763,20 +763,3 @@ is concentrated extracted gluten from wheat flour.
 
 I~recommend that you add around \qty{5}{\gram} of wheat gluten for every
 \qty{100}{\gram} of flour that you are using.
-
-\subsection[Incorporating seeds into the dough]{What's the best stage to
-incorporate inclusions (seeds) into the dough?}
-
-You can include seeds directly at the start when mixing the dough. If you use
-whole seeds such as wheat or rye kernels, soak them in water overnight and
-then rinse them before adding them to the dough. This makes sure that they
-are not crunchy and are soft enough when eating the bread. If you forgot to soak
-them you can cook the seeds for 10~minutes in hot water. Rinse them with cold
-water before adding them to your dough.
-
-If you want to sweeten the dough, your best option is to add sugar during the
-shaping stage. Sugar added too early in the process typically gets fermented until none of it
-remains. Adjust your shaping technique a little bit and spread your sugar
-mixture over a flattened-out dough. You can then roll the dough together,
-incorporating layers of sugar.
-