doc: Fix bitcoin-unterminated-logprintf tidy comments

* Move module description from test to LogPrintfCheck
* Add test doc
* Remove unused comment, see https://github.com/bitcoin/bitcoin/pull/26296/files#r1279351539

contrib/devtools/bitcoin-tidy/example_logprintf.cpp

@@ -2,9 +2,10 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-// Warn about any use of LogPrintf that does not end with a newline.
 #include <string>
 
+// Test for bitcoin-unterminated-logprintf
+
 enum LogFlags {
     NONE
 };
@@ -21,8 +22,6 @@ static inline void LogPrintf_(const std::string& logging_function, const std::st
 #define LogPrintLevel_(category, level, ...) LogPrintf_(__func__, __FILE__, __LINE__, category, level, __VA_ARGS__)
 #define LogPrintf(...) LogPrintLevel_(LogFlags::NONE, Level::None, __VA_ARGS__)
 
-// Use a macro instead of a function for conditional logging to prevent
-// evaluating arguments when logging for the category is not enabled.
 #define LogPrint(category, ...) \
     do {                        \
         LogPrintf(__VA_ARGS__); \

contrib/devtools/bitcoin-tidy/logprintf.h

@@ -9,6 +9,7 @@
 
 namespace bitcoin {
 
+// Warn about any use of LogPrintf that does not end with a newline.
 class LogPrintfCheck final : public clang::tidy::ClangTidyCheck
 {
 public: