vscode: exclude .patch files from trimTrailingWhitespace

Editing .patch files containing unmodified newlines
(represented by a single space) in vscode results in a dirty patch
as these spaces are stripped.

Set trimTrailingWhitespace = false for diff-language files (.patch)

Signed-off-by: Austin Lane <vidplace7@gmail.com>

.vscode/settings.json

@@ -1,6 +1,9 @@
 {
     "git.alwaysSignOff": true,
     "files.trimTrailingWhitespace": true,
+    "[diff]": {
+        "files.trimTrailingWhitespace": false
+    },
     "files.insertFinalNewline": true,
     "files.trimFinalNewlines": true,
     "files.eol": "\n",