Regenerate XDR with latest Protocol 23 version (#800)

* 1. Run the generator:

Change the commit hash to the right sha of stellar/stellar-xdr.
Add any new filenames (if needed: here Stellar-exporter.x for Galexie).
Run `make reset-xdr` from the project root.

* 2. Post-generation fixups to work around bugs or project-specific stuff:

* Move `xdr.Operation` into a hidden namespace to avoid conflicts with the
  SDK's `Operation`.
* Minimize the diff by running `sed -ie s/\"/\'/g types/{curr,next}.d.ts`
  (because the generator uses a different prettier config--this could
  probably be fixed in the generator itself, but this is easy enough
  for now).
* Add workarounds:
  - `type Hash = Opaque[];` is a necessary alias that doesn't get gen'd
  - `Hyper`, `UnsignedHyper`, and `ScSpecEventV0` need their signatures
    fixed because it should take a proper `Array` instead of a naked `[]`
    (enforced by `yarn lint`).
  - Some constants aren't generated correctly, ref. the linked issue

* 3. Accommodate XDR additions or renames:

* This accounts for any fields that encountered a rename as part
  of the new XDR version. In this case, `readBytes` was renamed to
  `diskReadBytes` because it's measured differently as a result of
  Core's state living in memory rather than on disk in most cases.
* It also accounts for the unused extension point actually having
  a name now, so `xdr.ExtensionPoint` needs to use the structure-
  specific `xdr.SorobanTransactionDataExt`, instead.

* Add docs to README for completeness

Author: Shaptic

Makefile

@@ -1,4 +1,4 @@
-XDR_BASE_URL_CURR=https://github.com/stellar/stellar-xdr/raw/529d5176f24c73eeccfa5eba481d4e89c19b1181
+XDR_BASE_URL_CURR=https://github.com/stellar/stellar-xdr/raw/4b7a2ef7931ab2ca2499be68d849f38190b443ca
 XDR_BASE_LOCAL_CURR=xdr/curr
 XDR_FILES_CURR= \
 	Stellar-SCP.x \
@@ -11,10 +11,11 @@ XDR_FILES_CURR= \
 	Stellar-contract-env-meta.x \
 	Stellar-contract-meta.x \
 	Stellar-contract-spec.x \
-	Stellar-contract-config-setting.x
+	Stellar-contract-config-setting.x \
+	Stellar-exporter.x
 XDR_FILES_LOCAL_CURR=$(addprefix xdr/curr/,$(XDR_FILES_CURR))
 
-XDR_BASE_URL_NEXT=https://github.com/stellar/stellar-xdr/raw/8c88608d0a20b01873056a5ec13be245e1f2aa27
+XDR_BASE_URL_NEXT=https://github.com/stellar/stellar-xdr/raw/4b7a2ef7931ab2ca2499be68d849f38190b443ca
 XDR_BASE_LOCAL_NEXT=xdr/next
 XDR_FILES_NEXT= \
 	Stellar-SCP.x \
@@ -27,7 +28,8 @@ XDR_FILES_NEXT= \
 	Stellar-contract-env-meta.x \
 	Stellar-contract-meta.x \
 	Stellar-contract-spec.x \
-	Stellar-contract-config-setting.x
+	Stellar-contract-config-setting.x \
+	Stellar-exporter.x
 XDR_FILES_LOCAL_NEXT=$(addprefix xdr/next/,$(XDR_FILES_NEXT))
 
 XDRGEN_COMMIT=master

README.md

@@ -146,8 +146,22 @@ earlier versions of Node, so the tests need to run on those versions.)
 
 #### Updating XDR definitions
 
+XDR updates are complicated due to the fact that you need workarounds for bugs
+in the generator, formatter, or a namespace adjustment.
+
 1. Make sure you have [Docker](https://www.docker.com/) installed and running.
-2. `make reset-xdr`
+2. Change the commit hash to the right version of [stellar-xdr](https://github.com/stellar/stellar-xdr) and add any filenames that might've been introduced.
+3. Run `make reset-xdr`
+4. Run `sed -ie s/\"/\'/g types/{curr,next}.d.ts` to minimize the diff (the generator's formatter uses `"` but the repo uses `'`).
+5. Move `xdr.Operation` into a hidden namespace to avoid conflicts with the SDK's `Operation`.
+6. Add generator workarounds:
+  * `type Hash = Opaque[]` is a necessary alias that doesn't get generated
+  * `Hyper`, `UnsignedHyper`, and `ScSpecEventV0` need their signatures
+    fixed because linting wants an `Array` instead of a naked `[]`.
+  * Some constants aren't generated correctly (e.g, Ctrl+F `SCSYMBOL_LIMIT` in `src/curr_generated.js`)
+7. Finally, make code adjustments related to the XDR (these are usually revealed by running the tests).
+
+As an example PR to follow, [stellar-base#800](https://github.com/stellar/js-stellar-base/pull/800) has detailed steps for each part of the process.
 
 ## Usage