Add moveLineUp/Down Shortcuts to the CodeMirror Editor

I don't know about others but, I organize my 1P-filters a lot. This would be useful.

I chose VS Code shortcuts. The shortcuts and their positioning can be debated.

Code is from CodeMirror itself: https://github.com/codemirror/codemirror5/blob/3bb9e7a38a9b95c66538676100fcced9cfe264ef/keymap/sublime.js#L244

src/lib/codemirror/lib/codemirror.js

@@ -6674,7 +6674,8 @@
   keyMap.pcDefault = {
     "Ctrl-A": "selectAll", "Ctrl-D": "deleteLine", "Ctrl-Z": "undo", "Shift-Ctrl-Z": "redo", "Ctrl-Y": "redo",
     "Ctrl-Home": "goDocStart", "Ctrl-End": "goDocEnd", "Ctrl-Up": "goLineUp", "Ctrl-Down": "goLineDown",
-    "Ctrl-Left": "goGroupLeft", "Ctrl-Right": "goGroupRight", "Alt-Left": "goLineStart", "Alt-Right": "goLineEnd",
+    "Ctrl-Left": "goGroupLeft", "Ctrl-Right": "goGroupRight",
+    "Alt-Up": "moveLineUp", "Alt-Down": "moveLineDown", "Alt-Left": "goLineStart", "Alt-Right": "goLineEnd",
     "Ctrl-Backspace": "delGroupBefore", "Ctrl-Delete": "delGroupAfter", "Ctrl-S": "save", "Ctrl-F": "find",
     "Ctrl-G": "findNext", "Shift-Ctrl-G": "findPrev", "Shift-Ctrl-F": "replace", "Shift-Ctrl-R": "replaceAll",
     "Ctrl-[": "indentLess", "Ctrl-]": "indentMore",
@@ -6692,7 +6693,8 @@
   keyMap.macDefault = {
     "Cmd-A": "selectAll", "Cmd-D": "deleteLine", "Cmd-Z": "undo", "Shift-Cmd-Z": "redo", "Cmd-Y": "redo",
     "Cmd-Home": "goDocStart", "Cmd-Up": "goDocStart", "Cmd-End": "goDocEnd", "Cmd-Down": "goDocEnd", "Alt-Left": "goGroupLeft",
-    "Alt-Right": "goGroupRight", "Cmd-Left": "goLineLeft", "Cmd-Right": "goLineRight", "Alt-Backspace": "delGroupBefore",
+    "Alt-Right": "goGroupRight", "Alt-Up": "moveLineUp", "Alt-Down": "moveLineDown",
+    "Cmd-Left": "goLineLeft", "Cmd-Right": "goLineRight", "Alt-Backspace": "delGroupBefore",
     "Ctrl-Alt-Backspace": "delGroupAfter", "Alt-Delete": "delGroupAfter", "Cmd-S": "save", "Cmd-F": "find",
     "Cmd-G": "findNext", "Shift-Cmd-G": "findPrev", "Cmd-Alt-F": "replace", "Shift-Cmd-Alt-F": "replaceAll",
     "Cmd-[": "indentLess", "Cmd-]": "indentMore", "Cmd-Backspace": "delWrappedLineLeft", "Cmd-Delete": "delWrappedLineRight",
@@ -7073,7 +7075,58 @@
       ensureCursorVisible(cm);
     }); },
     openLine: function (cm) { return cm.replaceSelection("\n", "start"); },
-    toggleOverwrite: function (cm) { return cm.toggleOverwrite(); }
+    toggleOverwrite: function (cm) { return cm.toggleOverwrite(); },
+    moveLineUp: function (cm) {
+      if (cm.isReadOnly()) return CodeMirror.Pass;
+      var ranges = cm.listSelections(), linesToMove = [], at = cm.firstLine() - 1, newSels = [];
+      for (var i = 0; i < ranges.length; ++i) {
+        var range = ranges[i], from = range.from().line - 1, to = range.to().line;
+        newSels.push({
+          anchor: Pos(range.anchor.line - 1, range.anchor.ch),
+          head: Pos(range.head.line - 1, range.head.ch)
+        });
+        if (range.to().ch == 0 && !range.empty()) --to;
+        if (from > at) linesToMove.push(from, to);
+        else if (linesToMove.length) linesToMove[linesToMove.length - 1] = to;
+        at = to;
+      }
+      cm.operation(function () {
+        for (var i = 0; i < linesToMove.length; i += 2) {
+          var from = linesToMove[i], to = linesToMove[i + 1];
+          var line = cm.getLine(from);
+          cm.replaceRange("", Pos(from, 0), Pos(from + 1, 0), "+swapLine");
+          if (to > cm.lastLine())
+            cm.replaceRange("\n" + line, Pos(cm.lastLine()), null, "+swapLine");
+          else
+            cm.replaceRange(line + "\n", Pos(to, 0), null, "+swapLine");
+        }
+        cm.setSelections(newSels);
+        cm.scrollIntoView();
+      });
+    },
+    moveLineDown: function (cm) {
+      if (cm.isReadOnly()) return CodeMirror.Pass;
+      var ranges = cm.listSelections(), linesToMove = [], at = cm.lastLine() + 1;
+      for (var i = ranges.length - 1; i >= 0; --i) {
+        var range = ranges[i], from = range.to().line + 1, to = range.from().line;
+        if (range.to().ch == 0 && !range.empty()) from--;
+        if (from < at) linesToMove.push(from, to);
+        else if (linesToMove.length) linesToMove[linesToMove.length - 1] = to;
+        at = to;
+      }
+      cm.operation(function () {
+        for (var i = linesToMove.length - 2; i >= 0; i -= 2) {
+          var from = linesToMove[i], to = linesToMove[i + 1];
+          var line = cm.getLine(from);
+          if (from == cm.lastLine())
+            cm.replaceRange("", Pos(from - 1), Pos(from), "+swapLine");
+          else
+            cm.replaceRange("", Pos(from, 0), Pos(from + 1, 0), "+swapLine");
+          cm.replaceRange(line + "\n", Pos(to, 0), null, "+swapLine");
+        }
+        cm.scrollIntoView();
+      });
+    },
   };