fixup: remove extraneous space after ==

Co-authored-by: Jan Schultke <[email protected]>

Author: dietmarkuehl

source/exec.tex

@@ -5883,7 +5883,7 @@
 \end{itemdescr}
 
 \begin{itemdecl}
-bool operator== (const task_scheduler& lhs, const task_scheduler& rhs) noexcept;
+bool operator==(const task_scheduler& lhs, const task_scheduler& rhs) noexcept;
 \end{itemdecl}
 
 \begin{itemdescr}