build: fix or silence new clang-tidy warnings

.clang-tidy

@@ -35,6 +35,7 @@ Checks: >
   -modernize-macro-to-enum,
   -readability-avoid-nested-conditional-operator,
   -readability-else-after-return,
+  -readability-enum-initial-value,
   -readability-function-size,
   -readability-isolate-declaration,
 
@@ -56,6 +57,7 @@ Checks: >
   -readability-function-cognitive-complexity,
   -readability-identifier-length,
   -readability-magic-numbers,
+  -readability-math-missing-parentheses,
   -readability-redundant-declaration, Conflicts with our header generation scripts,
   -readability-suspicious-call-argument,
 
@@ -65,6 +67,7 @@ Checks: >
   -cert-dcl51-cpp,
   -cert-exp42-c,
   -cert-flp37-c,
+  -cert-int09-c,
   -cert-msc24-c,
   -cert-msc33-c,
   -cppcoreguidelines-avoid-magic-numbers,

src/nvim/event/loop.h

@@ -9,8 +9,8 @@
 
 typedef void *WatcherPtr;
 
-#define _NOOP(x)
-KLIST_INIT(WatcherPtr, WatcherPtr, _NOOP)
+#define NOOP(x)
+KLIST_INIT(WatcherPtr, WatcherPtr, NOOP)
 
 struct loop {
   uv_loop_t uv;