Fix typos in tips

I'm not sure what the tip in Performance section is supposed to do, but
the slow part plots nothing, and the fast part doesn't run.

Author: QuLogic

cheatsheets.tex

@@ -1000,12 +1000,12 @@
     plot(X, Y, marker="o", ls="")  \hfill fast%
     \vskip.5\baselineskip
     %
-    \textcolor{red}{for i in range(n): plot(X[i]) \hfill slow}\\
-    plot(sum([x+[None] for x in X],[])) \hfill fast%
+    \textcolor{red}{for i in range(n): plot(i, X[i], "o") \hfill slow}\\
+    plot(X, marker="o", ls="") \hfill fast%
     \vskip.5\baselineskip
     %
-    \textcolor{red}{cla(), imshow(…), canvas.draw() \hfill slow}\\
-    im.set\_data(…), canvas.draw() \hfill fast%
+    \textcolor{red}{cla(); imshow(…); canvas.draw() \hfill slow}\\
+    im.set\_data(…); canvas.draw() \hfill fast%
     \vskip.1\baselineskip
     }
   \end{myboxed}

handout-beginner.tex

@@ -225,8 +225,8 @@ \subsection*{\rmfamily Tweak}
 \subsection*{\rmfamily Organize}
 % -----------------------------------------------------------------------------
 
-You can plot several data on the the same figure, but you can also
-split a figure in several subplots (named {\em Axes}): \medskip
+You can plot several data on the same figure, but you can also split a figure
+in several subplots (named {\em Axes}): \medskip
 
 % -----------------------------------------------------------------------------
 \begin{tabular}{@{}m{.821\linewidth}m{.169\linewidth}}

handout-intermediate.tex

@@ -185,10 +185,10 @@ \subsection*{\rmfamily Colors}
 \vspace{-1em}
 \subsection*{\rmfamily Size \& DPI}
 
-Consider a square figure to be included in a two-columns A4 paper with
-2cm margins on each side and a column separation of 1cm. The width of
-a figure is (21 - 2*2 - 1)/2 = 8cm. One inch being 2.54cm, figure size
-should be 3.15$\times$3.15 in.
+Consider a square figure to be included in a two-column A4 paper with
+2\,cm margins on each side and a column separation of 1\,cm. The width of
+a figure is (21 - 2*2 - 1)/2 = 8\,cm. One inch being 2.54\,cm, figure size
+should be 3.15$\times$3.15\,in.
 \begin{lstlisting}[]
  fig = plt.figure(figsize=(3.15, 3.15), dpi=50)
  plt.savefig("figure.pdf", dpi=600)

handout-tips.tex

@@ -153,7 +153,7 @@ \subsection*{\rmfamily Text outline}
 
 % -----------------------------------------------------------------------------
 \subsection*{\rmfamily Multiline plot}
-You can plot several lines at once using None as separator.
+You can plot several lines at once using {\em None} as separator.
 
 \begin{lstlisting}
  X,Y = [], []