Merge #17907: doc: Fix improper Doxygen inline comments

498cdbb Fix improper Doxygen inline comments (Ben Woosley)

Pull request description:

  The proper syntax is `//!<`
  http://www.doxygen.nl/manual/docblocks.html#memberdoc

  Identified via `-Wdocumentation`:

  ```
  In file included from ./util/system.h:26:
  ./util/settings.h:74:41: error: not a Doxygen trailing comment [-Werror,-Wdocumentation]
      const SettingsValue* begin() const; //<! Pointer to first non-negated value.
                                          ^~~~
                                          ///<
  ./util/settings.h:75:41: error: not a Doxygen trailing comment [-Werror,-Wdocumentation]
      const SettingsValue* end() const;   //<! Pointer to end of values.
                                          ^~~~
                                          ///<
  ./util/settings.h:76:41: error: not a Doxygen trailing comment [-Werror,-Wdocumentation]
      bool empty() const;                 //<! True if there are any non-negated values.
                                          ^~~~
                                          ///<
  ./util/settings.h:77:41: error: not a Doxygen trailing comment [-Werror,-Wdocumentation]
      bool last_negated() const;          //<! True if the last value is negated.
                                          ^~~~
                                          ///<
  ./util/settings.h:78:41: error: not a Doxygen trailing comment [-Werror,-Wdocumentation]
      size_t negated() const;             //<! Number of negated values.
                                          ^~~~
                                          ///<
  ```

ACKs for top commit:
  fanquake:
    ACK 498cdbb

Tree-SHA512: 2851fc1cbbcf700d198d82ce4923b2ef4a700f8ce19dff431ecf24f4e6fecda9fed1b4b4d148f3c1adfb6b0c6bff5d5315ee01bbcd855eb3d83e1a69b0c98893

Author: fanquake

src/util/settings.h

@@ -71,11 +71,11 @@ struct SettingsSpan {
     explicit SettingsSpan(const SettingsValue& value) noexcept : SettingsSpan(&value, 1) {}
     explicit SettingsSpan(const SettingsValue* data, size_t size) noexcept : data(data), size(size) {}
     explicit SettingsSpan(const std::vector<SettingsValue>& vec) noexcept;
-    const SettingsValue* begin() const; //<! Pointer to first non-negated value.
-    const SettingsValue* end() const;   //<! Pointer to end of values.
-    bool empty() const;                 //<! True if there are any non-negated values.
-    bool last_negated() const;          //<! True if the last value is negated.
-    size_t negated() const;             //<! Number of negated values.
+    const SettingsValue* begin() const; //!< Pointer to first non-negated value.
+    const SettingsValue* end() const;   //!< Pointer to end of values.
+    bool empty() const;                 //!< True if there are any non-negated values.
+    bool last_negated() const;          //!< True if the last value is negated.
+    size_t negated() const;             //!< Number of negated values.
 
     const SettingsValue* data = nullptr;
     size_t size = 0;