Finer control of abbreviate place names

Motivation: Including highest level place name when abbrevaiting from 
back is not always desirable. This change will allow you to request the 
highest level to keep while always trying to show SHOW_PEDIGREE_PLACES 
number of levels

Implementation: 

- add function backParts to Places
- keep lastParts as it is used by census handlers
- expand scope of SHOW_PEDIGREE_PLACES_SUFFIX so that 1=keep top level, 
2=only keep to 2nd highest level, etc.

Note: help text probably needs work

app/Place.php

@@ -165,6 +165,19 @@ public function firstParts(int $n): Collection
         return $this->parts->slice(0, $n);
     }
 
+    /**
+     * Extract the last parts of a place name, omitting top levels if possible.
+     *
+     * @param int $num : of parts to include - has highest priority
+     * @param int $omit : where to start counting backwards 1=top level, 2=next etc.
+     *
+     * @return Collection<string>
+     */
+    public function backParts(int $num, $omit): Collection
+    {
+        return $this->parts->slice(-($omit - 1) - $num, $num);
+    }
+
     /**
      * Extract the country (last parts) of a place name.
      *
@@ -280,10 +293,11 @@ public function fullName(bool $link = false): string
     public function shortName(bool $link = false): string
     {
         $SHOW_PEDIGREE_PLACES = (int) $this->tree->getPreference('SHOW_PEDIGREE_PLACES');
+        $SHOW_PEDIGREE_PLACES_SUFFIX = (int) $this->tree->getPreference('SHOW_PEDIGREE_PLACES_SUFFIX');
 
         // Abbreviate the place name, for lists
-        if ($this->tree->getPreference('SHOW_PEDIGREE_PLACES_SUFFIX')) {
-            $parts = $this->lastParts($SHOW_PEDIGREE_PLACES);
+        if ($SHOW_PEDIGREE_PLACES_SUFFIX) {
+            $parts = $this->backParts($SHOW_PEDIGREE_PLACES, $SHOW_PEDIGREE_PLACES_SUFFIX);
         } else {
             $parts = $this->firstParts($SHOW_PEDIGREE_PLACES);
         }

resources/views/admin/trees-preferences.phtml

@@ -594,7 +594,13 @@ use Illuminate\Support\Collection;
             <div class="col-sm-9">
                 <?= /* I18N: The placeholders are edit controls. Show the [first/last] [1/2/3/4/5] parts of a place name */ I18N::translate(
                     'Show the %1$s %2$s parts of a place name.',
-                    view('components/select', ['name' => 'SHOW_PEDIGREE_PLACES_SUFFIX', 'selected' => $tree->getPreference('SHOW_PEDIGREE_PLACES_SUFFIX'), 'options' => ['0' => I18N::translateContext('Show the [first/last] [N] parts of a place name.', 'first'), '1' => I18N::translateContext('Show the [first/last] [N] parts of a place name.', 'last')]]),
+                    view('components/select', ['name' => 'SHOW_PEDIGREE_PLACES_SUFFIX', 'selected' => $tree->getPreference('SHOW_PEDIGREE_PLACES_SUFFIX'),
+                      'options' => ['0' => I18N::translateContext('Show the [first/last] [N] parts of a place name.', 'first'),
+                                    '1' => I18N::translateContext('Show the [first/last] [N] parts of a place name.', 'last'),
+                                    '2' => I18N::translateContext('Show the [first/last] [N] parts of a place name.', 'last, omitting top level'),
+                                    '3' => I18N::translateContext('Show the [first/last] [N] parts of a place name.', 'last, omitting top 2 levels'),
+                                    '4' => I18N::translateContext('Show the [first/last] [N] parts of a place name.', 'last, omitting top 3 levels'),
+                                    ]]),
                     view('components/select-number', ['name' => 'SHOW_PEDIGREE_PLACES', 'selected' => $tree->getPreference('SHOW_PEDIGREE_PLACES'), 'options' => range(1, 9)])
                 ) ?>
                 <p class="small text-muted">