Bug 1826562 - Output hg diff output when verify-devtools-bundle fails. r=jdescottes.

We exclude  module-manifest.json from the diff as we already ignore it when
checking modified file.
We take this opportunity to use the proper exclude option from hg

Differential Revision: https://phabricator.services.mozilla.com/D174763

taskcluster/scripts/misc/verify-devtools-bundle.py

@@ -22,9 +22,13 @@ import json
 import subprocess
 import sys
 
+# Ignore module-manifest.json updates which can randomly happen when
+# building bundles.
+hg_exclude = "devtools/client/debugger/bin/module-manifest.json"
+
 print("Run `hg status devtools/`")
 status = (
-    subprocess.check_output(["hg", "status", "-n", "devtools/"])
+    subprocess.check_output(["hg", "status", "-n", "devtools/", "-X", hg_exclude])
     .decode("utf-8")
     .split("\n")
 )
@@ -39,11 +43,6 @@ for l in status:
         # Ignore empty lines
         continue
 
-    if "module-manifest.json" in l:
-        # Ignore module-manifest.json updates which can randomly happen when
-        # building bundles.
-        continue
-
     failures[l] = [
         {
             "path": l,
@@ -56,6 +55,11 @@ for l in status:
         }
     ]
 
+
+diff = subprocess.check_output(["hg", "diff", "devtools/", "-X", hg_exclude]).decode(
+    "utf-8"
+)
+
 # Revert all the changes created by `node bin/bundle.js`
 subprocess.check_output(["hg", "revert", "-C", "devtools/"])
 
@@ -76,4 +80,6 @@ if len(failures) > 0:
     for failure in failures:
         print(failure)
 
+    print(f"diff:{diff}")
+
     sys.exit(1)