mention markupsafe in deprecation message

src/markupsafe/_native.py

diff --git a/src/markupsafe/_native.py b/src/markupsafe/_native.py
index 1a3f214..6f7eb7a 100644
--- a/src/markupsafe/_native.py
+++ b/src/markupsafe/_native.py
@@ -68,7 +68,7 @@
 
     warnings.warn(
         "'soft_unicode' has been renamed to 'soft_str'. The old name"
-        " will be removed in version 2.1.",
+        " will be removed in MarkupSafe 2.1.",
         DeprecationWarning,
         stacklevel=2,
     )

src/markupsafe/_speedups.c

diff --git a/src/markupsafe/_speedups.c b/src/markupsafe/_speedups.c
index 7b7e57f..44967b1 100644
--- a/src/markupsafe/_speedups.c
+++ b/src/markupsafe/_speedups.c
@@ -260,7 +260,7 @@
 	PyErr_WarnEx(
 		PyExc_DeprecationWarning,
 		"'soft_unicode' has been renamed to 'soft_str'. The old name"
-		" will be removed in version 2.1.",
+		" will be removed in MarkupSafe 2.1.",
 		2
 	);
 	return soft_str(self, s);