[DOCS] Remove unneeded // CONSOLE comments from snippets (#48763)

* Removes several unneeded `// CONSOLE` comments from snippets in the update by query docs
* Updates the docs README file to remove outdated `// CONSOLE` instructions

docs/README.asciidoc

@@ -26,19 +26,12 @@ Snippets marked with `[source,console]` are automatically annotated with
 tested by the command `./gradlew -pdocs check`. To test just the docs from a
 single page, use e.g. `./gradlew -ddocs integTestRunner --tests "*rollover*"`.
 
-NOTE: Previously we use `// CONSOLE` instead of `[source,console]`. This worked
-well for a long time so you'll see it all over early branches but we're phasing
-it out because it requires some unpleasant hackery on the docs build side.
-
-NOTE: If you have an elasticsearch-extra folder alongside your elasticsearch
-folder, you must temporarily rename it when you are testing 6.3 or later branches.
-
-By default each `// CONSOLE` snippet runs as its own isolated test. You can
-manipulate the test execution in the following ways:
+By default each `[source,console]` snippet runs as its own isolated test. You
+can manipulate the test execution in the following ways:
 
 * `// TEST`: Explicitly marks a snippet as a test. Snippets marked this way
-are tests even if they don't have `// CONSOLE` but usually `// TEST` is used
-for its modifiers:
+are tests even if they don't have `[source,console]` but usually `// TEST` is
+used for its modifiers:
   * `// TEST[s/foo/bar/]`: Replace `foo` with `bar` in the generated test. This
   should be used sparingly because it makes the snippet "lie". Sometimes,
   though, you can use it to make the snippet more clear. Keep in mind that

docs/reference/docs/update-by-query.asciidoc

@@ -305,7 +305,6 @@ POST twitter/_update_by_query?conflicts=proceed
   }
 }
 --------------------------------------------------
-// CONSOLE
 // TEST[setup:twitter]
 
 <1> The query must be passed as a value to the `query` key, in the same
@@ -318,7 +317,6 @@ Update documents in multiple indices:
 --------------------------------------------------
 POST twitter,blog/_update_by_query
 --------------------------------------------------
-// CONSOLE
 // TEST[s/^/PUT twitter\nPUT blog\n/]
 
 Limit the update by query operation to shards that a particular routing value:
@@ -327,7 +325,6 @@ Limit the update by query operation to shards that a particular routing value:
 --------------------------------------------------
 POST twitter/_update_by_query?routing=1
 --------------------------------------------------
-// CONSOLE
 // TEST[setup:twitter]
 
 By default update by query uses scroll batches of 1000. 
@@ -337,7 +334,6 @@ You can change the batch size with the `scroll_size` parameter:
 --------------------------------------------------
 POST twitter/_update_by_query?scroll_size=100
 --------------------------------------------------
-// CONSOLE
 // TEST[setup:twitter]
 
 [[docs-update-by-query-api-source]]
@@ -361,7 +357,6 @@ POST twitter/_update_by_query
   }
 }
 --------------------------------------------------
-// CONSOLE
 // TEST[setup:twitter]
 
 Note that `conflicts=proceed` is not specified in this example. In this case, a
@@ -402,7 +397,6 @@ PUT _ingest/pipeline/set-foo
 }
 POST twitter/_update_by_query?pipeline=set-foo
 --------------------------------------------------
-// CONSOLE
 // TEST[setup:twitter]