libcamera: controls: Fix minor error in documentation

Fix a small spelling mistake in the ControlInfoMap documentation.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

src/libcamera/controls.cpp

@@ -592,7 +592,7 @@ std::string ControlInfo::toString() const
  *
  * The ControlInfoMap class describes controls supported by an object as an
  * unsorted map of ControlId pointers to ControlInfo instances. Unlike the
- * standard std::unsorted_map<> class, it is designed the be immutable once
+ * standard std::unsorted_map<> class, it is designed to be immutable once
  * constructed, and thus only exposes the read accessors of the
  * std::unsorted_map<> base class.
  *