Add Context::set_selections(std::vector<Selection>)

This methods avoids updating the context selection needlessly as
they are going to get replaced anyway.

src/context.cc

@@ -202,6 +202,11 @@ std::vector<String> Context::selections_content() const
     return contents;
 }
 
+void Context::set_selections(std::vector<Selection> sels)
+{
+    *m_selections = std::move(sels);
+}
+
 void Context::begin_edition()
 {
     if (m_edition_level >= 0)

src/context.hh

@@ -51,6 +51,7 @@ public:
     SelectionList& selections();
     const SelectionList& selections() const;
     std::vector<String>  selections_content() const;
+    void set_selections(std::vector<Selection> sels);
 
     void change_buffer(Buffer& buffer);
 

src/normal.cc

@@ -725,7 +725,7 @@ void keep(Context& context, int)
         }
         if (keep.empty())
             throw runtime_error("no selections remaining");
-        context.selections() = std::move(keep);
+        context.set_selections(std::move(keep));
     });
 }
 
@@ -749,7 +749,7 @@ void keep_pipe(Context& context, int)
             }
             if (keep.empty())
                 throw runtime_error("no selections remaining");
-            context.selections() = std::move(keep);
+            context.set_selections(std::move(keep));
     });
 }
 template<bool indent_empty = false>
@@ -1213,7 +1213,7 @@ void undo(Context& context, int)
     {
         auto ranges = compute_modified_ranges(buffer, timestamp);
         if (not ranges.empty())
-            context.selections() = std::move(ranges);
+            context.set_selections(std::move(ranges));
     }
     else if (not res)
         context.print_status({ "nothing left to undo", get_color("Information") });
@@ -1229,7 +1229,7 @@ void redo(Context& context, int)
     {
         auto ranges = compute_modified_ranges(buffer, timestamp);
         if (not ranges.empty())
-            context.selections() = std::move(ranges);
+            context.set_selections(std::move(ranges));
     }
 
     else if (not res)