Add/update source block delimeters (#83624)

Asciidoc source blocks are to be delimited with four dashes. This adds missing delimiters, and updates some that contained only three dashes. It matters for parsing purposes.

docs/reference/how-to/fix-common-cluster-issues.asciidoc

@@ -692,9 +692,9 @@ see the number of active threads in each thread pool and
 how many tasks are queued, how many have been rejected, and how many have completed. 
 
 [source,console]
----
+----
 GET /_cat/thread_pool?v&s=t,n&h=type,name,node_name,active,queue,rejected,completed
----
+----
 
 **Inspect the hot threads on each node**
 
@@ -704,9 +704,9 @@ to determine if the thread has sufficient
 resources to progress and gauge how quickly it is progressing.
 
 [source,console]
----
+----
 GET /_nodes/hot_threads
----
+----
 
 **Look for long running tasks**
 

docs/reference/sql/functions/conditional.asciidoc

@@ -86,10 +86,12 @@ E.g.:
 for the following query:
 
 [source, sql]
+----
 CASE WHEN a = 1 THEN null
      WHEN a > 2 THEN 10
      WHEN a > 5 THEN 'foo'
 END
+----
 
 an error message would be returned, mentioning that *'foo'* is of data type *keyword*,
 which does not match the expected data type *integer* (based on result *10*).
@@ -105,6 +107,7 @@ interesting than every single value, CASE can create custom buckets as in the
 following example:
 
 [source, sql]
+----
 SELECT count(*) AS count,
   CASE WHEN NVL(languages, 0) = 0 THEN 'zero'
     WHEN languages = 1 THEN 'one'
@@ -115,7 +118,7 @@ SELECT count(*) AS count,
 FROM employees
 GROUP BY lang_skills
 ORDER BY lang_skills;
-
+----
 With this query, one can create normal grouping buckets for values _0, 1, 2, 3_ with
 descriptive names, and every value _>= 4_ falls into the _multilingual_ bucket.
 
@@ -282,7 +285,9 @@ include-tagged::{sql-specs}/docs/docs.csv-spec[iifWithoutDefaultValue]
 expression. E.g.:
 
 [source, sql]
+----
 IIF(a = 1, 'one', IIF(a = 2, 'two', IIF(a = 3, 'three', 'many')))
+----
 =================