fix: Avoid else after return in mappings bzl (#923)

pkg/mappings.bzl

diff --git a/pkg/mappings.bzl b/pkg/mappings.bzl
index 789c00f..9e7653a 100644
--- a/pkg/mappings.bzl
+++ b/pkg/mappings.bzl
@@ -31,7 +31,7 @@
 load("//pkg:providers.bzl", "PackageDirsInfo", "PackageFilegroupInfo", "PackageFilesInfo", "PackageSymlinkInfo")
 load("//pkg/private:util.bzl", "get_repo_mapping_manifest")
 
-# TODO(#333): strip_prefix module functions should produce unique outputs.  In
+# TODO(#333): strip_prefix module functions should produce unique outputs. In
 # particular, this one and `_sp_from_pkg` can overlap.
 _PKGFILEGROUP_STRIP_ALL = "."
 
@@ -43,14 +43,12 @@
 def _sp_from_pkg(path = ""):
     if path.startswith("/"):
         return path[1:]
-    else:
-        return path
+    return path
 
 def _sp_from_root(path = ""):
     if path.startswith("/"):
         return path
-    else:
-        return "/" + path
+    return "/" + path
 
 strip_prefix = struct(
     _doc = """pkg_files `strip_prefix` helper.  Instructs `pkg_files` what to do with directory prefixes of files.
@@ -148,21 +146,20 @@
 
     if path_norm.startswith(to_strip_norm):
         return path_norm[len(to_strip_norm):]
-    elif src_file.is_directory and (path_norm + "/") == to_strip_norm:
+    if src_file.is_directory and (path_norm + "/") == to_strip_norm:
         return ""
-    else:
-        # Avoid user surprise by failing if prefix stripping doesn't work as
-        # expected.
-        #
-        # We already leave enough breadcrumbs, so if File.owner() returns None,
-        # this won't be a problem.
-        failmsg = "Could not strip prefix '{}' from file {} ({})".format(to_strip, str(src_file), str(src_file.owner))
-        if src_file.is_directory:
-            failmsg += """\n\nNOTE: prefix stripping does not operate within TreeArtifacts (directory outputs)
+
+    # Avoid user surprise by failing if prefix stripping doesn't work as expected.
+    #
+    # We already leave enough breadcrumbs, so if File.owner() returns None,
+    # this won't be a problem.
+    failmsg = "Could not strip prefix '{}' from file {} ({})".format(to_strip, str(src_file), str(src_file.owner))
+    if src_file.is_directory:
+        failmsg += """\n\nNOTE: prefix stripping does not operate within TreeArtifacts (directory outputs)
 
 To strip the directory named by the TreeArtifact itself, see documentation for the `renames` attribute.
 """
-        fail(failmsg)
+    fail(failmsg)
 
 # The below routines make use of some path checking magic that may difficult to
 # understand out of the box.  This following table may be helpful to demonstrate
@@ -189,8 +186,7 @@
     # File.owner returns a Label structure
     if file.owner == None:
         fail("File {} ({}) has no owner attribute; cannot continue".format(file, file.path))
-    else:
-        return file.owner
+    return file.owner
 
 def _relative_workspace_root(label):
     # Helper function that returns the workspace root relative to the bazel File
@@ -219,7 +215,7 @@
     )
 
 def _pkg_files_impl(ctx):
-    # The input sources are already known.  Let's calculate the destinations...
+    # The input sources are already known. Let's calculate the destinations...
 
     # Exclude excludes
     srcs = []  # srcs is source File objects, not Targets
@@ -263,7 +259,7 @@
         # rename_src.files is a depset
         rename_src_files = rename_src.files.to_list()
 
-        # Need to do a length check before proceeding.  We cannot rename
+        # Need to do a length check before proceeding. We cannot rename
         # multiple files simultaneously.
         if len(rename_src_files) != 1:
             fail(