Help: Add `.. versionadded` directives to commands documentation

This change ony concerns directives that appear in the document body.

The guidelines for inserting version directives:

 * Baseline version is CMake 3.0, i.e. directives start at 3.1.
 * Always use `.. versionadded::` directive, avoid ad-hoc version
   references. Exception: policy pages.
 * For new command signatures, put `versionadded` on a separate line
   after the signature.
 * For a group of new signatures in a new document section,
   a single version note at the beginning of the section is sufficient.
 * For new options, put `versionadded` on a separate line before
   option description.
 * If all the option descriptions in the list are short one-liners,
   it's fine to put `versionadded` on the same line as the description.
 * If multiple option descriptions in close proximity would have
   the same ..versionadded directive, consider adding a single
   directive after the list, mentioning all added options.
 * For compact value lists and sub-option lists, put a single
  `versionadded` directive after the list mentioning all additions.
 * When a change is described in a single paragraph, put
   `versionadded` into that paragraph.
 * When only part of the paragraph has changed, separate the changed
   part if it doesn't break the flow. Otherwise, write a follow-up
   clarification paragraph and apply version directive to that.
 * When multiple version directives are close by, order earlier
   additions before later additions.
 * Indent related lists and code blocks to include them in the scope
   of `versionadded` directive.

Issue: #19715

1 files changed, 15 insertions, 13 deletions

diff --git a/Help/command/get_source_file_property.rst b/Help/command/get_source_file_property.rst
index 76ed776..1e0ea9f 100644
--- a/Help/command/get_source_file_property.rst
+++ b/Help/command/get_source_file_property.rst
@@ -19,19 +19,21 @@ command and if still unable to find the property, ``variable`` will be set to
 an empty string.
 
 By default, the source file's property will be read from the current source
-directory's scope, but this can be overridden with one of the following
-sub-options:
-
-``DIRECTORY <dir>``
-  The source file property will be read from the ``<dir>`` directory's
-  scope.  CMake must already know about that source directory, either by
-  having added it through a call to :command:`add_subdirectory` or ``<dir>``
-  being the top level source directory.  Relative paths are treated as
-  relative to the current source directory.
-
-``TARGET_DIRECTORY <target>``
-  The source file property will be read from the directory scope in which
-  ``<target>`` was created (``<target>`` must therefore already exist).
+directory's scope.
+
+.. versionadded:: 3.18
+  Directory scope can be overridden with one of the following sub-options:
+
+  ``DIRECTORY <dir>``
+    The source file property will be read from the ``<dir>`` directory's
+    scope.  CMake must already know about that source directory, either by
+    having added it through a call to :command:`add_subdirectory` or ``<dir>``
+    being the top level source directory.  Relative paths are treated as
+    relative to the current source directory.
+
+  ``TARGET_DIRECTORY <target>``
+    The source file property will be read from the directory scope in which
+    ``<target>`` was created (``<target>`` must therefore already exist).
 
 Use :command:`set_source_files_properties` to set property values.  Source
 file properties usually control how the file is built. One property that is