Make clang-tidy suggest stdint.h int types (#2820)

.clang-tidy

@@ -101,6 +101,8 @@ CheckOptions:
     value:           '10'
   - key:             google-readability-namespace-comments.SpacesBeforeComments
     value:           '2'
+  - key:             google-runtime-int.TypeSuffix
+    value:           '_t'
   - key:             modernize-loop-convert.MaxCopySize
     value:           '16'
   - key:             modernize-loop-convert.MinConfidence