deprecated.xml Remove the extra parentheses (#4021)

Author: mmalferov

appendices/migration84/deprecated.xml

@@ -85,11 +85,11 @@ function foo(T1 $a, ?T2 $b, T3 $c) {}
     Raising a number to the power of a negative number is equivalent to taking
     the reciprocal of the number raised to the positive opposite of the power.
     That is, <literal>10<superscript>-2</superscript></literal> is the same as
-    <literal>1 / (10<superscript>2</superscript>)</literal>.
+    <literal>1 / 10<superscript>2</superscript></literal>.
     Therefore raising <literal>0</literal> to the power of a negative number
     corresponds to dividing by <literal>0</literal>, i.e.
     <literal>0<superscript>-2</superscript></literal> is the same as
-    <literal>1 / (0<superscript>2</superscript>)</literal>, or
+    <literal>1 / 0<superscript>2</superscript></literal>, or
     <literal>1 / 0</literal>. Thus, this behavior has been deprecated.
    </simpara>