Add severity argument to GoToDiagnostic actions (#33995)

This PR adds a `severity` argument so severity can be defined when
navigating through diagnostics. This allows keybinds like the following:

```json
{
  "] e": ["editor::GoToDiagnostic", { "severity": "error" }],
  "[ e": ["editor::GoToDiagnostic", { "severity": "error" }]
}
```

I've added test comments and a test. Let me know if there's anything
else you need!

Release Notes:

- Add `severity` argument to `editor::GoToDiagnostic`,
`editor::GoToPreviousDiagnostic`, `project_panel::SelectNextDiagnostic`
and `project_panel::SelectPrevDiagnostic` actions

assets/keymaps/default-linux.json

@@ -475,8 +475,8 @@
       "ctrl-/": ["editor::ToggleComments", { "advance_downwards": false }],
       "ctrl-u": "editor::UndoSelection",
       "ctrl-shift-u": "editor::RedoSelection",
-      "f8": "editor::GoToDiagnostic",
-      "shift-f8": "editor::GoToPreviousDiagnostic",
+      "f8": ["editor::GoToDiagnostic", { "severity": { "min": "hint", "max": "error" } }],
+      "shift-f8": ["editor::GoToPreviousDiagnostic", { "severity": { "min": "hint", "max": "error" } }],
       "f2": "editor::Rename",
       "f12": "editor::GoToDefinition",
       "alt-f12": "editor::GoToDefinitionSplit",

assets/keymaps/default-macos.json

@@ -528,8 +528,8 @@
       "cmd-/": ["editor::ToggleComments", { "advance_downwards": false }],
       "cmd-u": "editor::UndoSelection",
       "cmd-shift-u": "editor::RedoSelection",
-      "f8": "editor::GoToDiagnostic",
-      "shift-f8": "editor::GoToPreviousDiagnostic",
+      "f8": ["editor::GoToDiagnostic", { "severity": { "min": "hint", "max": "error" } }],
+      "shift-f8": ["editor::GoToPreviousDiagnostic", { "severity": { "min": "hint", "max": "error" } }],
       "f2": "editor::Rename",
       "f12": "editor::GoToDefinition",
       "alt-f12": "editor::GoToDefinitionSplit",