[Squash] nits

Co-authored-by: Anna Henningsen <[email protected]>

Author: jasnell

doc/api/buffer.md

@@ -3286,18 +3286,20 @@ added: REPLACEME
 
 * `data` {any} The Base64-encoded input string.
 
-Decodes a string of Base64-encoded data into ASCII (Latin1).
+Decodes a string of Base64-encoded data into bytes, and encodes those bytes
+into a string using Latin-1 (ISO-8859-1).
 
-The `data` may be any JavaScript-value that can be coerced into a string.
+The `data` may be any JavaScript value that can be coerced into a string.
 
 ### `buffer.btoa(data)`
 <!-- YAML
 added: REPLACEME
 -->
 
-* `data` {any} An ASCII (Latin1) string.
+* `data` {any} A Latin-1 string.
 
-Encodes a string of ASCII characters into a Base64-encoded string.
+Decodes a string into bytes using Latin-1 (ISO-8859), and encodes those bytes
+into a string using Base64.
 
 The `data` may be any JavaScript-value that can be coerced into a string.