[NFC][clang-tidy] reword diagnostic note in definitions-in-headers (#106862)

`make as inline` made little sense here, so I changed the `make` to
`mark`
and added `the definition` as well.

Author: 5chmidti

clang-tools-extra/clang-tidy/misc/DefinitionsInHeadersCheck.cpp

@@ -102,7 +102,7 @@ void DefinitionsInHeadersCheck::check(const MatchFinder::MatchResult &Result) {
     // inline is not allowed for main function.
     if (FD->isMain())
       return;
-    diag(FD->getLocation(), /*Description=*/"make as 'inline'",
+    diag(FD->getLocation(), "mark the definition as 'inline'",
          DiagnosticIDs::Note)
         << FixItHint::CreateInsertion(FD->getInnerLocStart(), "inline ");
   } else if (const auto *VD = dyn_cast<VarDecl>(ND)) {

clang-tools-extra/docs/ReleaseNotes.rst

@@ -124,6 +124,10 @@ Changes in existing checks
   false positive when member initialization depends on a structured binging
   variable.
 
+- Improved :doc:`misc-definitions-in-headers
+  <clang-tidy/checks/misc/definitions-in-headers>` check by rewording the
+  diagnostic note that suggests adding ``inline``.
+
 - Improved :doc:`modernize-use-std-format
   <clang-tidy/checks/modernize/use-std-format>` check to support replacing
   member function calls too.

clang-tools-extra/test/clang-tidy/checkers/misc/definitions-in-headers.hpp

@@ -2,7 +2,7 @@
 
 int f() {
 // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: function 'f' defined in a header file; function definitions in header files can lead to ODR violations [misc-definitions-in-headers]
-// CHECK-MESSAGES: :[[@LINE-2]]:5: note: make as 'inline'
+// CHECK-MESSAGES: :[[@LINE-2]]:5: note: mark the definition as 'inline'
 // CHECK-FIXES: inline int f() {
   return 1;
 }