feat docs: a few more additions to changelog

Tests: протестировано локально и в CI
commit_hash:54473433f3190a276e51734e534d5f5f9b658e44

Author: apolukhin

core/src/logging/log_test.cpp

@@ -181,15 +181,20 @@ TEST_F(LoggingTest, Call) {
 }
 
 TEST_F(LoggingTest, CallFormat) {
-    /// [Example lambda-based logging usage]
-    std::map<int, int> map{{1, 2}, {2, 3}, {3, 4}};
-    LOG_ERROR() << [&map](auto& out) {
-        for (const auto& [key, value] : map) {
-            out.Format("{}={}, ", key, value);
-        }
-    };
-    /// [Example lambda-based logging usage]
-    EXPECT_EQ("1=2, 2=3, 3=4, ", LoggedText());
+    const int user_id = 42;
+    std::string ip_address = "127.0.0.1";
+    std::string_view expected_result = "User 42 logged in from 127.0.0.1";
+
+    /// [Example format bad logging usage]
+    LOG_INFO() << fmt::format("User {} logged in from {}", user_id, ip_address);
+    /// [Example format bad logging usage]
+    EXPECT_EQ(expected_result, LoggedText());
+    ClearLog();
+
+    /// [Example format-based logging usage]
+    LOG_INFO("User {} logged in from {}", user_id, ip_address);
+    /// [Example format-based logging usage]
+    EXPECT_EQ(expected_result, LoggedText());
 }
 
 TEST_F(LoggingTest, LoggingContainerElementFields) {

scripts/docs/en/userver/logging.md

@@ -150,18 +150,14 @@ LOG_INFO(<format-string>, <args>...);
 
 #### Examples
 
-@snippet logging/log_test.cpp Example inline formatting usage
-
 **Basic Usage**
 Instead of:
-```cpp
-LOG_INFO() << fmt::format("User {} logged in from {}", user_id, ip_address);
-```
+
+@snippet logging/log_test.cpp Example format bad logging usage
 
 Use:
-```cpp
-LOG_INFO("User {} logged in from {}", user_id, ip_address);
-```
+
+@snippet logging/log_test.cpp Example format-based logging usage
 
 This writes the formatted message directly to the log buffer.
 

scripts/docs/en/userver/roadmap_and_changelog.md

@@ -36,7 +36,8 @@ Changelog news also go to the
 
 ### Release v2.9
 
-* Logging now supports `fmt` formatting in macro: `LOG_INFO("This is {} message", "informational");`
+* Logging now supports `fmt` formatting in macro `LOG_INFO("User {} logged in from {}", user_id, ip_address);` and
+  lambda formatting. See @ref scripts/docs/en/userver/logging.md for more info.
 * PostgreSQL driver now can disable all the statements logging via static config option `statement-log-mode` 
 * ClickHouse driver now supports doubles in the queries.
 * YDB now can be used with GCC compiler, not only Clang. YDB still requires C++20 support