Update tests/presubmit.sh with modern syntax for Fuchsia bugs

Replaces "fxb/#" with the Monorail syntax "fuchsia:#".
This updates https://swiftshader-review.googlesource.com/c/SwiftShader/+/44129.

Bug: None
Change-Id: I9dc0e617cdec2d1a8b980ee7aca2c718ce4021d6
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/46328
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: David Dorwin <ddorwin@google.com>
diff --git a/tests/presubmit.sh b/tests/presubmit.sh
index 3b32cd7..20b0b61 100755
--- a/tests/presubmit.sh
+++ b/tests/presubmit.sh
@@ -40,14 +40,13 @@
 
 # Validate commit message
 function run_bug_in_commit_msg() {
-  git log -1 --pretty=%B | grep -E '^(Bug|Issue|Fixes):(\s?)((((b|fxb)\/)|(\w+:))([0-9]+)|[^0-9]+)$|(^Regres:)|(^PiperOrigin-RevId:)'
+  git log -1 --pretty=%B | grep -E '^(Bug|Issue|Fixes):(\s?)(((b\/)|(\w+:))([0-9]+)|[^0-9]+)$|(^Regres:)|(^PiperOrigin-RevId:)'
 
   if [ $? -ne 0 ]
   then
     echo "${red}Git commit message must have a Bug: line"
     echo "followed by a bug ID in the form b/# for Buganizer bugs or"
-    echo "project:# for Monorail bugs (e.g. 'Bug: chromium:123') or"
-    echo "fxb/# For Fuchsia bugs (e.g. 'Bug: fxb/123')."
+    echo "project:# for Monorail bugs (e.g. 'Bug: chromium:123' or 'Bug: fuchsia:123')."
     echo "Omit any digits when no ID is required (e.g. 'Bug: fix build').${normal}"
     return 1
   fi