Update cheatsheet.fr.md

12.temporary_ins/08.conservative-vector-fields/20.conservative-vector-fields-properties/20.overview/cheatsheet.fr.md

@@ -536,6 +536,7 @@ $`\begin{align}
 \displaystyle\color{brown}{\large{\mathbf{\displaystyle\int_A^B\overrightarrow{F}_{tot}\cdot\overrightarrow{dl}}}} & =\int_A^B \alpha\,\overrightarrow{X}\cdot\overrightarrow{dl}\\
 & =\int_A^B \alpha\,\big(-\,\overrightarrow{grad}\,\phi_X\big) \cdot\overrightarrow{dl} \\
 & =-\,\int_A^B \alpha\,d\phi_X \\
+\end{align}`$
 <br>
 <br>
 $`\begin{align}