.editorconfig should not set root = true.

This prevents developers from using parent .editorconfig files to add
additional directives that are intended to apply to all checkouts (e.g.
V8 + Chromium). In my case, for example, I add line-length guideline
markers for various filetypes and disable `trim_trailing_whitespace` for
.md files.

This also adds a comment link to the editorconfig website (since many
people don't know what this file is) and alphabetizes.

Bug: none
Change-Id: I7c0992c9224d0c25fc69cf9ce5013088f16e99dc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/5773128
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Shu-yu Guo <syg@chromium.org>
Auto-Submit: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/main@{#95571}

.editorconfig

@@ -1,9 +1,9 @@
-root = true
+# editorconfig.org
 
 [*]
 charset = utf-8
-indent_style = space
-indent_size = 2
 end_of_line = lf
+indent_size = 2
+indent_style = space
 insert_final_newline = true
 trim_trailing_whitespace = true