Add .jj to default file exclusion (#21708)

Relates to #21538

Release Notes:

- Added `**/.jj` to the default file exclusion list.

assets/settings/default.json

@@ -685,6 +685,7 @@
     "**/.git",
     "**/.svn",
     "**/.hg",
+    "**/.jj",
     "**/CVS",
     "**/.DS_Store",
     "**/Thumbs.db",

crates/worktree/src/worktree_settings.rs

@@ -40,6 +40,7 @@ pub struct WorktreeSettingsContent {
     ///   "**/.git",
     ///   "**/.svn",
     ///   "**/.hg",
+    ///   "**/.jj",
     ///   "**/CVS",
     ///   "**/.DS_Store",
     ///   "**/Thumbs.db",

docs/src/configuring-zed.md

@@ -994,6 +994,7 @@ The result is still `)))` and not `))))))`, which is what it would be by default
   "**/.git",
   "**/.svn",
   "**/.hg",
+  "**/.jj"
   "**/CVS",
   "**/.DS_Store",
   "**/Thumbs.db",