[docs] Update maintainer guide to include CMAKE_REQUIRE_FIND_PACKAGE. (…

…#23321)

Co-authored-by: Alexander Neumann <you@example.com>

docs/maintainers/maintainer-guide.md

@@ -200,23 +200,27 @@ When defining a feature that captures an optional dependency,
 ensure that the dependency will not be used accidentally when the feature is not explicitly enabled.
 
 ```cmake
+set(CMAKE_DISABLE_FIND_PACKAGE_ZLIB ON)
+set(CMAKE_REQUIRE_FIND_PACKAGE_ZLIB OFF)
 if ("zlib" IN_LIST FEATURES)
   set(CMAKE_DISABLE_FIND_PACKAGE_ZLIB OFF)
-else()
-  set(CMAKE_DISABLE_FIND_PACKAGE_ZLIB ON)
+  set(CMAKE_REQUIRE_FIND_PACKAGE_ZLIB ON)
 endif()
 
 vcpkg_cmake_configure(
   SOURCE_PATH ${SOURCE_PATH}
   OPTIONS
     -DCMAKE_DISABLE_FIND_PACKAGE_ZLIB=${CMAKE_DISABLE_FIND_PACKAGE_ZLIB}
+    -DCMAKE_REQUIRE_FIND_PACKAGE_ZLIB=${CMAKE_REQUIRE_FIND_PACKAGE_ZLIB}
 )
 ```
 
 The snippet below using `vcpkg_check_features()` is equivalent,  [see the documentation](vcpkg_check_features.md).
 
 ```cmake
 vcpkg_check_features(OUT_FEATURE_OPTIONS FEATURE_OPTIONS
+  FEATURES
+    "zlib"    CMAKE_REQUIRE_FIND_PACKAGE_ZLIB
   INVERTED_FEATURES
     "zlib"    CMAKE_DISABLE_FIND_PACKAGE_ZLIB
 )
@@ -228,7 +232,7 @@ vcpkg_cmake_configure(
 )
 ```
 
-Note that `ZLIB` in the above is case-sensitive. See the [cmake documentation](https://cmake.org/cmake/help/v3.15/variable/CMAKE_DISABLE_FIND_PACKAGE_PackageName.html) for more details.
+Note that `ZLIB` in the above is case-sensitive. See the [CMAKE_DISABLE_FIND_PACKAGE_PackageName](https://cmake.org/cmake/help/v3.22/variable/CMAKE_DISABLE_FIND_PACKAGE_PackageName.html) and [CMAKE_REQUIRE_FIND_PACKAGE_PackageName](https://cmake.org/cmake/help/v3.22/variable/CMAKE_REQUIRE_FIND_PACKAGE_PackageName.html) documnetation for more details.
 
 ### Place conflicting libs in a `manual-link` directory
 
@@ -328,6 +332,8 @@ Because of this, it is preferable to patch the buildsystem directly when setting
 
 When making changes to a library, strive to minimize the final diff. This means you should _not_ reformat the upstream source code when making changes that affect a region. Also, when disabling a conditional, it is better to add a `AND FALSE` or `&& 0` to the condition than to delete every line of the conditional.
 
+Don't add patches if the port is outdated and updating the port to a newer released version would solve the same issue. vcpkg prefers updating ports over patching outdated versions unless the version bump breaks a considerable amount of dependent ports.
+
 This helps to keep the size of the vcpkg repository down as well as improves the likelihood that the patch will apply to future code versions.
 
 ### Do not implement features in patches