servo: Merge #17749 - Extra space check (from SergeevPavel:extra-space-check); r=jdm

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Add tidy check for keywords with more than one space afterwards.

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #17700 (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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Source-Repo: https://github.com/servo/servo
Source-Revision: 7d95fb8e49dd0eb9fa9efb9d70008f5f9bf20a83

servo/python/tidy/servo_tidy/tidy.py

@@ -584,6 +584,12 @@ def check_rust(file_name, lines):
             # -> () is unnecessary
             (r"-> \(\)", "encountered function signature with -> ()", no_filter),
         ]
+        keywords = ["if", "let", "mut", "extern", "as", "impl", "fn", "struct", "enum", "pub", "mod",
+                    "use", "in", "ref", "type", "where", "trait"]
+        extra_space_after = lambda key: (r"(?<![A-Za-z0-9\-_]){key}  ".format(key=key),
+                                         "extra space after {key}".format(key=key),
+                                         lambda match, line: not is_attribute)
+        regex_rules.extend(map(extra_space_after, keywords))
 
         for pattern, message, filter_func in regex_rules:
             for match in re.finditer(pattern, line):