This filters the build-picker type lists to only show types that have
already been placed in the current game, making it simpler to get to
build matching features.
These windows now share a common code base for choosing and display class and types.
An additional text filter is added to search types by name instead of just classes.
After sorting and filter lists for GUI, we often shirnk them to reduce size. However this has very little benefit:
1) The memory has already been allocated, so it doesn't prevent that memory being required.
2) It causes a new allocation and copy when the vector is shrunk, actually using more memory.
3) The list is in window state, so the lifetime is only while the window is open.
4) When a filter is clearer, the original size will be needed again, which will cause another allocation.
In fact it is beneficial to reserve to the known maximum in most cases, so do that instead.
GUIList has a pointer only to the start of each sort/filter func list, which has the potential for UB as it is unable to validate that the selected sort or filter type is in range.
Use a std::span instead and check if the selected type is in range before using it.
NWidgetMatrix modifies its child widget's index to indicate which element
is to be drawn, which now causes issues with code that does not know about
stuffing extra data into the index.
Instead, let NWidgetMatrix store the currently processing element, and
retrieve this information from the matrix widget while child widgets are
being drawn.
This means only widgets that are children of NWidgetMatrix need to know
anything about their extra data.
It used to be a random sentinel for end-of-(widget-)list that was used to tell
that no action has taken place yet. Since the last action is practically the
widget that was pressed, add the sentinel to that enumeration.
This simplifies processing nwidget parts as, unlike the remaining length, the pointer to the end of the list never changes. This is the same principle as we use(d) for tracking end instead of length for C-style strings.
And this removes 160~ instances of the lengthof() macro.
Having to choose between DropDownListStringItem, DropDownListCharStringItem, and DropDownListParamStringItem depending on whether to draw a StringID, a raw string, or a StringID with extra parameters was needlessly complex.
Instead, allow passing a StringID or raw string to DropDownListStringItem. This will preformat the StringID into a raw string, and can therefore accept parameters via the normal SetDParam mechanism.
This also means that strings no longer need to be formatted on every draw.
Hotkeys are now initialized inline, and use std::vector instead of
separate static C-arrays and std::string instead of char *. The list end
marker is no longer required.
This function returns an iterator, either to the selected item or the
container's end.
This makes handling the result more robust as indices are not used.
