Update textbook.fr.md

00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/05.classical-mechanics/vector-analysis/textbook.fr.md

@@ -302,7 +302,7 @@ $`\;\Longrightarrow\left|\begin{array}{l}\overrightarrow{U}\cdot\overrightarrow{
 \\ \,
 \\
  \overrightarrow{U}\cdot\overrightarrow{V}=-||\overrightarrow{U}||\cdot||\overrightarrow{V}||
- \,si\, \widehat{\overrightarrow{U},\overrightarrow{V}}=\pi\right.`$ 
+ \,si\, \widehat{\overrightarrow{U},\overrightarrow{V}}=\pi\end{array}\right.`$ 
  
  $`\overrightarrow{U}`$ et $`\overrightarrow{V}`$ sont colinéaires 
 $`\;\Longrightarrow\left|\overrightarrow{U}\cdot\overrightarrow{V}=+||\overrightarrow{U}||\cdot