Fewer includes of WaveformSettings.h, SpectrogramSettings.h...

... See ultimate origin of some of the deleted lines at 4724c6a

Whatever change it is that needs loading by LoadPrefs -- do it instead right
after any possibility of changes to the relevant preferences, in the Commit()
functions of SpectrumPrefs and WaveforPrefs

src/menus/EditMenus.cpp

@@ -22,8 +22,6 @@
 #include "../commands/ScreenshotCommand.h"
 #include "../export/Export.h"
 #include "../prefs/PrefsDialog.h"
-#include "../prefs/SpectrogramSettings.h"
-#include "../prefs/WaveformSettings.h"
 #include "../tracks/labeltrack/ui/LabelTrackView.h"
 #include "../widgets/AudacityMessageBox.h"
 

src/prefs/PrefsDialog.cpp

@@ -62,7 +62,6 @@
 #include "TracksBehaviorsPrefs.h"
 #include "WarningsPrefs.h"
 // #include "WaveformPrefs.h"
-#include "WaveformSettings.h"
 #include "ExtImportPrefs.h"
 
 #ifdef EXPERIMENTAL_MIDI_OUT
@@ -857,9 +856,6 @@ void PrefsDialog::OnOK(wxCommandEvent & WXUNUSED(event))
 
    wxTheApp->AddPendingEvent(wxCommandEvent{ EVT_PREFS_UPDATE });
 
-   WaveformSettings::defaults().LoadPrefs();
-   SpectrogramSettings::defaults().LoadPrefs();
-
    if( IsModal() )
       EndModal(true);
    else
@@ -949,9 +945,6 @@ wxString PrefsPanel::HelpPageName()
 void DoReloadPreferences( AudacityProject &project )
 {
    {
-      SpectrogramSettings::defaults().LoadPrefs();
-      WaveformSettings::defaults().LoadPrefs();
-
       GlobalPrefsDialog dialog(
          &GetProjectFrame( project ) /* parent */, &project );
       wxCommandEvent Evt;

src/prefs/SpectrumPrefs.cpp

@@ -501,10 +501,11 @@ bool SpectrumPrefs::Commit()
 
    mCommitted = true;
    SpectrogramSettings::Globals::Get().SavePrefs(); // always
-   if (!mWt || mDefaulted) {
    SpectrogramSettings *const pSettings = &SpectrogramSettings::defaults();
+   if (!mWt || mDefaulted) {
       pSettings->SavePrefs();
    }
+   pSettings->LoadPrefs(); // always; in case Globals changed
 
    return true;
 }

src/prefs/WaveformPrefs.cpp

@@ -177,12 +177,12 @@ bool WaveformPrefs::Commit()
       }
    }
 
+   WaveformSettings *const pSettings = &WaveformSettings::defaults();
    if (!mWt || mDefaulted) {
-      WaveformSettings *const pSettings =
-         &WaveformSettings::defaults();
       *pSettings = mTempSettings;
       pSettings->SavePrefs();
    }
+   pSettings->LoadPrefs(); // always; in case Globals changed
 
    mTempSettings.ConvertToEnumeratedDBRange();