patch 9.1.1144: no way to create raw strings from a blob

Problem:  no way to create raw strings from a blob
Solution: support the "encoding": "none" option
          to create raw strings (which may be invalid!)
          (Bakudankun)

closes: #16666

Signed-off-by: Bakudankun <bakudankun@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index 344dfdf..80b8a9c 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -1,4 +1,4 @@
-*builtin.txt*	For Vim version 9.1.  Last change: 2025 Feb 17
+*builtin.txt*	For Vim version 9.1.  Last change: 2025 Feb 23
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -1309,10 +1309,14 @@
 		items:
 		    encoding	Decode the bytes in {blob} using this
 				encoding.  The value is a |String|.  See
-				|encoding-names| for the supported values.
+				|encoding-names| for the supported values
+				(plus the special value "none").
 							*E1515*
-		An error is given and an empty List is returned if
-		an invalid byte sequence is encountered in {blob},
+		When current 'encoding' is "utf-8", an error is given and an
+		empty List is returned if an invalid byte sequence is
+		encountered in {blob}.  To suppress this validation and get
+		potentially invalid string, set "encoding" in {options} to
+		"none".
 
 		Returns an empty List if blob is empty.
 
@@ -10645,7 +10649,8 @@
 
 		The argument {options} is a |Dict| and supports the following
 		items:
-		    encoding	Encode the characters using this encoding.
+		    encoding	Convert the characters using this encoding
+				before making the Blob.
 				The value is a |String|.  See |encoding-names|
 				for the supported values.