Update cheatsheet.en.md

12.temporary_ins/90.electromagnetism-in-vacuum/10.maxwell-equations/20.overview/cheatsheet.en.md

@@ -264,7 +264,7 @@ _thus revolutionizing physics._
    \end{array}`$**   
    <br>
    * This equation plays an *important role in Neumann's induction phenomena*.   
-   _The quantity $`\oint_{\Gamma\leftrightarrow S} \overrightarrow{E}\cdot\overrightarrow{dl}`$_
+   _The quantity_ $`\oint_{\Gamma\leftrightarrow S} \overrightarrow{E}\cdot\overrightarrow{dl}`$
    _with the historically imperfect name "electromotive force (emf)", homogeneous to a voltage, is the origin of an electric current_
    _flowing through the contour $`\Gamma`$ if it represents a conductive circuit._