Fix formatting and potential NULL concatenation bug

Code quality improvements:
- Standardize comment formatting to include space after "--":
  - b3_table_pgstattuple.sql: Fix 4 comment lines
  - b4_btree_pgstattuple.sql: Fix 4 comment lines
  - l1_lock_trees.sql: Fix inline comment
  - v2_autovacuum_progress_and_queue.sql: Fix inline comment

Bug fix:
- l2_lock_trees.sql: Add ELSE clause to CASE statement to prevent
  NULL concatenation when level = 1, which would make the entire
  format() result NULL

These changes ensure consistent comment formatting across SQL files
and fix a subtle bug that could cause query results to be NULL.

Author: claude

sql/b3_table_pgstattuple.sql

@@ -1,8 +1,8 @@
 --Table bloat (requires pgstattuple; expensive)
 
---https://github.com/dataegret/pg-utils/tree/master/sql
---pgstattuple extension required
---WARNING: without table name/mask query will read all available tables which could cause I/O spikes
+-- https://github.com/dataegret/pg-utils/tree/master/sql
+-- pgstattuple extension required
+-- WARNING: without table name/mask query will read all available tables which could cause I/O spikes
 select nspname,
 relname,
 pg_size_pretty(relation_size + toast_relation_size) as total_size,
@@ -22,7 +22,7 @@ from (
     left join pg_namespace n on (n.oid = c.relnamespace)
     where nspname not in ('pg_catalog', 'information_schema')
     and nspname !~ '^pg_toast' and relkind = 'r'
-    --put your table name/mask here
+    -- put your table name/mask here
     and relname ~ ''
 ) t
 order by (toast_free_space + relation_size - (relation_size - free_space)*100/fillfactor) desc

sql/b4_btree_pgstattuple.sql

@@ -1,8 +1,8 @@
 --B-tree indexes bloat (requires pgstattuple; expensive)
 
---https://github.com/dataegret/pg-utils/tree/master/sql
---pgstattuple extension required
---WARNING: without index name/mask query will read all available indexes which could cause I/O spikes
+-- https://github.com/dataegret/pg-utils/tree/master/sql
+-- pgstattuple extension required
+-- WARNING: without index name/mask query will read all available indexes which could cause I/O spikes
 with data as (
   select
     schemaname as schema_name,
@@ -25,7 +25,7 @@ with data as (
   join pg_class c_table on p.relid = c_table.oid
   where
     pg_get_indexdef(p.indexrelid) like '%USING btree%'
-    --put your index name/mask here
+    -- put your index name/mask here
     and indexrelname ~ ''
 )
 select

sql/l1_lock_trees.sql

@@ -28,7 +28,7 @@ with recursive l as (
 select (clock_timestamp() - a.xact_start)::interval(0) as ts_age,
        (clock_timestamp() - a.state_change)::interval(0) as change_age,
        a.datname,a.usename,a.client_addr,
-       --w.obj wait_on_object,
+       -- w.obj wait_on_object,
        tree.pid,replace(a.state, 'idle in transaction', 'idletx') state,
        lvl,(select count(*) from tree p where p.path ~ ('^'||tree.path) and not p.path=tree.path) blocked,
        case when tree.pid=any(tree.dl) then '!>' else repeat(' .', lvl) end||' '||trim(left(regexp_replace(a.query, e'\\s+', ' ', 'g'),100)) query

sql/l2_lock_trees.sql

@@ -61,7 +61,7 @@ select
   format(
     '%s %s%s',
     lpad('[' || pid::text || ']', 7, ' '),
-    repeat('.', level - 1) || case when level > 1 then ' ' end,
+    repeat('.', level - 1) || case when level > 1 then ' ' else '' end,
     left(query, 1000)
   ) as query
 from tree

sql/v2_autovacuum_progress_and_queue.sql

@@ -30,7 +30,7 @@ with table_opts as (
   from pg_stat_progress_vacuum
 )
 select
-  --vacuum_settings.oid,
+  -- vacuum_settings.oid,
   coalesce(
     coalesce(nullif(vacuum_settings.nspname, 'public') || '.', '') || vacuum_settings.relname, -- current DB
     format('[something in "%I"]', p.datname)