[Backport 7.x] Update generated low-level client code (#5220)

* Exclude QueryWatches from API renaming
* Add cat tasks patch
* Low-level code gen

(cherry picked from commit b22f06d)

Author: stevejgordon

src/ApiGenerator/Domain/Code/CsharpNames.cs

@@ -37,7 +37,7 @@ string Replace(string original, string ns, string find, string replace, string[]
 
 			var namespaceRenames = new Dictionary<string, (string find, string replace, string[] exceptions)>
 			{
-				{ "Watcher", (find: "Watch", replace: "", exceptions: new string[0]) },
+				{ "Watcher", (find: "Watch", replace: "", exceptions: new string[]{ "QueryWatches" }) },
 				{ "Indices", (find: "Index", replace: "", exceptions: new [] { "SimulateIndexTemplate" }) },
 				{ "CrossClusterReplication", (find: "Ccr", replace: "", exceptions: new string[0]) },
 				{ "IndexLifecycleManagement", (find: "Ilm", replace: "", exceptions: new string[0]) },

src/ApiGenerator/RestSpecification/Core/bulk.json

@@ -5,6 +5,11 @@
       "description":"Allows to perform multiple index/update/delete operations in a single request."
     },
     "stability":"stable",
+    "visibility":"public",
+    "headers":{
+      "accept": [ "application/json"],
+      "content_type": ["application/x-ndjson"]
+    },
     "url":{
       "paths":[
         {

src/ApiGenerator/RestSpecification/Core/cat.aliases.json

@@ -5,6 +5,10 @@
       "description":"Shows information about currently configured aliases to indices including filter and routing infos."
     },
     "stability":"stable",
+    "visibility":"public",
+    "headers":{
+      "accept": [ "text/plain", "application/json"]
+    },
     "url":{
       "paths":[
         {

src/ApiGenerator/RestSpecification/Core/cat.allocation.json

@@ -5,6 +5,10 @@
       "description":"Provides a snapshot of how many shards are allocated to each data node and how much disk space they are using."
     },
     "stability":"stable",
+    "visibility":"public",
+    "headers":{
+      "accept": [ "text/plain", "application/json"]
+    },
     "url":{
       "paths":[
         {

src/ApiGenerator/RestSpecification/Core/cat.count.json

@@ -5,6 +5,10 @@
       "description":"Provides quick access to the document count of the entire cluster, or individual indices."
     },
     "stability":"stable",
+    "visibility":"public",
+    "headers":{
+      "accept": [ "text/plain", "application/json"]
+    },
     "url":{
       "paths":[
         {

src/ApiGenerator/RestSpecification/Core/cat.fielddata.json

@@ -5,6 +5,10 @@
       "description":"Shows how much heap memory is currently being used by fielddata on every data node in the cluster."
     },
     "stability":"stable",
+    "visibility":"public",
+    "headers":{
+      "accept": [ "text/plain", "application/json"]
+    },
     "url":{
       "paths":[
         {

src/ApiGenerator/RestSpecification/Core/cat.health.json

@@ -5,6 +5,10 @@
       "description":"Returns a concise representation of the cluster health."
     },
     "stability":"stable",
+    "visibility":"public",
+    "headers":{
+      "accept": [ "text/plain", "application/json"]
+    },
     "url":{
       "paths":[
         {

src/ApiGenerator/RestSpecification/Core/cat.help.json

@@ -5,6 +5,10 @@
       "description":"Returns help for the Cat APIs."
     },
     "stability":"stable",
+    "visibility":"public",
+    "headers":{
+      "accept": [ "text/plain" ]
+    },
     "url":{
       "paths":[
         {

src/ApiGenerator/RestSpecification/Core/cat.indices.json

@@ -5,6 +5,10 @@
       "description":"Returns information about indices: number of primaries and replicas, document counts, disk size, ..."
     },
     "stability":"stable",
+    "visibility":"public",
+    "headers":{
+      "accept": [ "text/plain", "application/json"]
+    },
     "url":{
       "paths":[
         {

src/ApiGenerator/RestSpecification/Core/cat.master.json

@@ -5,6 +5,10 @@
       "description":"Returns information about the master node."
     },
     "stability":"stable",
+    "visibility":"public",
+    "headers":{
+      "accept": [ "text/plain", "application/json"]
+    },
     "url":{
       "paths":[
         {