Disable bugprone-macro-parentheses and let clang-format insert braces. (#3825)

-
[bugprone-macro-parentheses](https://clang.llvm.org/extra/clang-tidy/checks/bugprone/macro-parentheses.html)
-- this is just a false positive issue, I don't think it's helping us
catch bugs.
-
[InsertBraces](https://clang.llvm.org/docs/ClangFormatStyleOptions.html#insertbraces)
-- although there's a warning about this creating issues due to
incomplete semantic information, it seems to be happy with our code, and
allows clang-format to fix something that clang-tidy would otherwise
warn about.

toolchain/parse/node_kind.h

@@ -95,7 +95,6 @@ class NodeKind : public CARBON_ENUM_BASE(NodeKind) {
 #include "toolchain/parse/node_kind.def"
 
 constexpr int NodeKind::ValidCount = 0
-// NOLINTNEXTLINE(bugprone-macro-parentheses)
 #define CARBON_PARSE_NODE_KIND(Name) +1
 #include "toolchain/parse/node_kind.def"
     ;