docs/api: note charset parameter may be sent

Since at least commit 099adaa in 2013
the Git LFS client has included a "charset=utf-8" parameter in some
or all of the Content-Type headers it sends to server API endpoints.

As noted in git-lfs#5775, we do not at present mention this parameter in
our API documentation, and the "charset" parameter is not required
by any IETF RFCs for MIME types other than "text/*" types, so we
note that servers should be prepared to accept this header parameter
but that it is not required.

h/t KalleOlaviNiemitalo for the suggestion

Author: chrisd8088

docs/api/basic-transfers.md

@@ -141,4 +141,7 @@ Git LFS clients send:
 < HTTP/1.1 200 OK
 ```
 
+The client may also include a `charset=utf-8` parameter in the
+`Content-Type` header, which servers should be prepared to accept.
+
 A 200 response means that the object exists on the server.

docs/api/batch.md

@@ -19,6 +19,9 @@ headers. The request and response bodies are JSON.
     Accept: application/vnd.git-lfs+json
     Content-Type: application/vnd.git-lfs+json
 
+The client may also include a `charset=utf-8` parameter in the
+`Content-Type` header, which servers should be prepared to accept.
+
 See the [Authentication doc](./authentication.md) for more info on how LFS
 gets authorizes Batch API requests.
 

docs/api/locking.md

@@ -18,6 +18,9 @@ All File Locking requests require the following HTTP headers:
     Accept: application/vnd.git-lfs+json
     Content-Type: application/vnd.git-lfs+json
 
+The client may also include a `charset=utf-8` parameter in the
+`Content-Type` header, which servers should be prepared to accept.
+
 See the [Authentication doc](./authentication.md) for more info on how LFS
 gets authorizes Batch API requests.