Auto merge of #12755 - tsawada:patch-1, r=ConnorGBrewster

Fix flag compose in runservo.sh

This fixes following error when running runservo.sh:

$ ./runservo.sh
Unrecognized option: '-'.
$

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- [ ] `./mach build -d` does not report any errors
- [ ] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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s/-S--pref/-S --pref/

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python/servo/package_commands.py

@@ -229,7 +229,7 @@ class PackageCommands(CommandBase):
                     delete(dir_to_package + '/build/' + f)
             print("Writing runservo.sh")
             # TODO: deduplicate this arg list from post_build_commands
-            servo_args = ['-w', '-b', '-M', '-S'
+            servo_args = ['-w', '-b', '-M', '-S',
                           '--pref', 'dom.mozbrowser.enabled',
                           '--pref', 'dom.forcetouch.enabled',
                           '--pref', 'shell.builtin-key-shortcuts.enabled=false',