[processing] When searching in toolbox, ignore order of words

Eg, allows you to search "line merge" and find the "Merge lines"
algorithm. Should make it easier for users who don't know the
exact name to find algorithms.

python/plugins/processing/gui/ProcessingToolbox.py

@@ -108,7 +108,7 @@ def textChanged(self):
         text = self.searchBox.text().strip(' ').lower()
         for item in list(self.disabledProviderItems.values()):
             item.setHidden(True)
-        self._filterItem(self.algorithmTree.invisibleRootItem(), text)
+        self._filterItem(self.algorithmTree.invisibleRootItem(), [t for t in text.split(' ') if t])
         if text:
             self.algorithmTree.expandAll()
             self.disabledWithMatchingAlgs = []
@@ -137,10 +137,15 @@ def _filterItem(self, item, text):
             item.setHidden(not show)
             return show
         elif isinstance(item, (TreeAlgorithmItem, TreeActionItem)):
-            # hide = bool(text) and (text not in item.text(0).lower())
-            hide = bool(text) and not any(text in t for t in [item.text(0).lower(), item.data(0, Qt.UserRole).lower()])
+            # hide if every part of text is not contained somewhere in either the item text or item user role
+            item_text = [item.text(0).lower(), item.data(0, Qt.UserRole).lower()]
             if isinstance(item, TreeAlgorithmItem):
-                hide = hide and (text not in item.alg.commandLineName())
+                item_text.append(item.alg.commandLineName())
+
+            hide = bool(text) and not all(
+                any(part in t for t in item_text)
+                for part in text)
+
             item.setHidden(hide)
             return not hide
         else: