Small fixes (#155)

* Fix various typos and references or links

- Misuse of product macro the x sign did not appear
- Use macro for milligrams
- Some refes were without hyperlink for some reason ?
- confusion between section and subsections
- a little grammar.. exact value not absolute, don't think a negative
  amount of flower was ever an option :D

* Use siunitx for temperature everywhere

Apparently some files escaped my script last time, or messed up in git
merge... Anyway fixed now and should be more consistent.

* Simplify Fermentolysis table

I woudl hope this is more clear with less lines.

* Remove double bottomrule

* Fix grammar

* Use correct font familly in preface

Small corrections on font familly and extra space for signature.
TODO: I did not change the paragraph breaking but we might want to
revisit it later.

* Fix wrong percentage range

fixes https://github.com/hendricius/the-sourdough-framework/issues/156

book/intro/preface.tex

@@ -34,7 +34,7 @@ Some years passed, and I~eventually began my studies in the small German city of
 For the first time, I~was faced with shopping for my own bread. It was never
 on my mind to actually start baking it for myself. I~would just buy 
 a good loaf while shopping at the supermarket. My favorite variety
-was a Schwarzbrot, Korn an Korn. It’s a very dark and hearty rye bread
+was a \emph{Schwarzbrot: Korn an Korn}. It’s a very dark and hearty rye bread
 with added berries and sunflower seeds. Being a little naïve,
 I'd never before examined the packaging of what I~was buying. One day, that
 changed.
@@ -118,7 +118,7 @@ share open source software.
 
 Now, when baking great bread, you also need to learn certain techniques. I~figured it would be
 easier to share these techniques in video form. Thus, my YouTube channel was born. I~chose
-the name \emph{The Bread Code} to capture my engineering-oriented approach to bread. It took some
+the name \texttt{The Bread Code} to capture my engineering-oriented approach to bread. It took some
 time to get right, but after choosing more engaging thumbnails and titles for
 the videos I~made, the channel started gaining viewers.
 
@@ -180,7 +180,7 @@ scientific references where possible and to clearly distinguish between facts an
 I~hope you have fun reading this and that you learn more about the fascinating world of bread
 making, and it is my sincere wish that this work provides you with the solid toolchain that I~wish
 I'd had access to when starting my own journey with bread.
-
-Thank you.
-
-Hendrik
+\vspace{\baselineskip}\linebreak
+\noindent \mbox{Thank you.}
+\vspace{\baselineskip}\linebreak
+\noindent Hendrik