Fix typos in demo

Very minor typo/grammar corrections.

demo/demo.tex

@@ -71,7 +71,7 @@ \section{Titleformats}
  This frame uses the \texttt{smallcaps} titleformat.
 
  \begin{alertblock}{Potential Problems}
- Be aware, that not every font supports small caps. If for example you typeset your presentation with pdfTeX and the Computer Modern Sans Serif font, every text in smallcaps will be typeset with the Computer Modern Serif font instead.
+ Be aware that not every font supports smallcaps. If for example you typeset your presentation with pdfTeX and the Computer Modern Sans Serif font, every text in smallcaps will be typeset with the Computer Modern Serif font instead.
  \end{alertblock}
 \end{frame}
 }
@@ -84,7 +84,7 @@ \section{Titleformats}
  \begin{alertblock}{Potential problems}
  As this titleformat also uses smallcaps you face the same problems as with the \texttt{smallcaps} titleformat. Additionally this format can cause some other problems. Please refer to the documentation if you consider using it.
 
- As a rule of thumb: Just use it for plaintext-only titles.
+ As a rule of thumb: just use it for plaintext-only titles.
  \end{alertblock}
 \end{frame}
 }
@@ -133,7 +133,7 @@ \section{Elements}
  \column{0.33\textwidth}
  Items
  \begin{itemize}
- \item Milk \item Eggs \item Potatos
+ \item Milk \item Eggs \item Potatoes
  \end{itemize}
 
  \column{0.33\textwidth}