Add "bestFit" column attribute serialisation

include/xlnt/worksheet/column_properties.hpp

@@ -51,6 +51,12 @@ public:
     /// </summary>
     optional<std::size_t> style;
 
+    /// <summary>
+    /// Is this column sized to fit its content as best it can
+    /// serialise if true
+    /// </summary>
+    bool best_fit = false;
+
     /// <summary>
     /// If true, this column will be hidden
     /// </summary>

source/detail/serialization/xlsx_consumer.cpp

@@ -588,6 +588,9 @@ std::string xlsx_consumer::read_worksheet_begin(const std::string &rel_id)
                     ? is_true(parser().attribute("customWidth")) : false;
                 auto hidden = parser().attribute_present("hidden")
                     ? is_true(parser().attribute("hidden")) : false;
+                auto best_fit = parser().attribute_present("bestFit")
+                    ? is_true(parser().attribute("bestFit"))
+                    : false;
 
                 expect_end_element(qn("spreadsheetml", "col"));
 
@@ -607,6 +610,7 @@ std::string xlsx_consumer::read_worksheet_begin(const std::string &rel_id)
 
                     props.hidden = hidden;
                     props.custom_width = custom;
+                    props.best_fit = best_fit;
                     ws.add_column_properties(column, props);
                 }
             }

source/detail/serialization/xlsx_producer.cpp

@@ -2362,6 +2362,11 @@ void xlsx_producer::write_worksheet(const relationship &rel)
             write_attribute("width", (props.width.get() * 7 + 5) / 7);
         }
 
+        if (props.best_fit)
+        {
+            write_attribute("bestFit", write_bool(true));
+        }
+
         if (props.style.is_set())
         {
             write_attribute("style", props.style.get());