wrap: Updated docs

docs/markdown/Wrap-dependency-system-manual.md

@@ -83,6 +83,12 @@ revision = head
   directory name. Needed when the source file does not have a leading
   directory.
 
+Since *0.55.0* it is possible to use only the `source_filename` and
+`patch_filename` value in a .wrap file (without `source_url` and `patch_url`) to
+specify a local archive in the `subprojects/packagefiles` directory. The `*_hash`
+entries are optional when using this method. This method should be prefered over
+the old `packagecache` approach described below.
+
 Since *0.49.0* if `source_filename` or `patch_filename` is found in the
 project's `subprojects/packagecache` directory, it will be used instead
 of downloading the file, even if `--wrap-mode` option is set to

docs/markdown/snippets/wrap_patch.md

@@ -0,0 +1,6 @@
+## Local wrap source and patch files
+
+It is now possible to use the `patch_filename` and `source_filename` value in a
+`.wrap` file without `*_url` to specify a local source / patch file. All local
+files must be located in the `subprojects/packagefiles` directory. The `*_hash`
+entries are optional with this setup.