fix(docs): fix a typo repo-copy => copy-repo

Also lint grammar in the surrounding paragraphs.

docs/source/spec_format.rst

@@ -66,10 +66,10 @@ Details about the ``SRCS`` format:
       * ``false``: Do not fetch submodules.
       * ``recursive``: [Default] Fetch submodules recursively.
 
-    * ``repo-copy``: Automatically copy the VCS repository to the build directory.
+    * ``copy-repo``: Automatically copy VCS metadata to the build directory.
 
-      * ``true``: Copy the VCS repository prior to the building process, replaces ``acbs_copy_git``.
-      * ``false``: [Default] Do not copy the VCS repository. However you can still use ``acbs_copy_git``.
+      * ``true``: Copy VCS metadata prior to the building process, replaces ``acbs_copy_git``.
+      * ``false``: [Default] Do not copy VCS metadata. However you can still use ``acbs_copy_git``.
 
 To specify multiple options, you can join the options with semicolons (``;``) like this: