[fix] correct cluster-management, data-governance, load/query/database/function statement doc errors

[boluor]

Summary

Fixes 25 small documentation issues across cluster-management, data-governance, DML, load-and-export, data-query, database, and function SQL-statement docs. Each item below is independent.

cluster-management

• MODIFY-BACKEND.md — table headers 属性 / 影响 were Chinese in the English doc; replaced with Property / Effect.
• MODIFY-FRONTEND-HOSTNAME.md — typo NOD_PRIV → NODE_PRIV.
• ADD-FOLLOWER.md / ADD-OBSERVER.md / DROP-FOLLOWER.md / DROP-OBSERVER.md — a usage note read use[\SHOW FRONTENDS`](./SHOW-FRONTENDS.md)command` with no spaces around the markdown link; DROP-FOLLOWER also dropped the verb "use". Rewritten with proper spacing.
• DROP-BROKER.md — SQL example ended with . instead of ;.
• ALTER-STORAGE-POLICY.md — typo PROPERTIE → PROPERTIES in the syntax block and the inline reference.
• ALTER-STORAGE-VAULT.md — text said the listed hdfs property fields were "prohibited"; corrected to "allowed" (the list describes properties the user may set).
• CREATE-STORAGE-POLICY.md — SQL syntax contained full-width ， and ｜ characters; replaced with ASCII.
• CANCEL-WARM-UP.md — syntax requires the JOB keyword but the example omitted it; example aligned with syntax.
• SHOW-CACHE-HOTSPOT.md — a :::info admonition was unclosed (no ::: before the next ## Syntax).

data-governance

• CREATE-ROW-POLICY.md — frontmatter description and the body Description paragraph said "Explain can view the rewritten execution plan." (a leftover from the EXPLAIN doc); rewritten to actually describe row policies.
• CREATE-ROW-POLICY.md — two example CREATE ROW POLICY statements used the same name test_row_policy_3; renamed the second to test_row_policy_4.
• CREATE-SQL_BLOCK_RULE.md — example creates rule test_rule, but the simulated error message echoed order_analysis_rule; corrected.
• SHOW-SQL_BLOCK_RULE.md — stray | at the end of a parameter-description line; two result tables also had misaligned borders.

DML / load-and-export / data-query / database / function

• MERGE-INTO.md — heading ### Duplicate join behavior¶ ended with a stray pilcrow ¶; removed.
• SHOW-LAST-INSERT.md — keywords line SHOW, LASR ,INSERT typo corrected to SHOW, LAST, INSERT. Informal section markers grammar: / illustrate: replaced with canonical ## Syntax / ## Return Value headings.
• CREATE-ROUTINE-LOAD.md — a frontmatter link pointed at a non-existent anchor #Example-of-importing-Json-format-data; corrected to the actual anchor in each version (#import-examples for current / 3.x / 4.x; #load-example for 2.1). Frontmatter description was truncated mid-sentence; completed.
• ALTER-ROUTINE-LOAD.md / PAUSE-ROUTINE-LOAD.md / RESUME-ROUTINE-LOAD.md / STOP-ROUTINE-LOAD.md / SHOW-CREATE-ROUTINE-LOAD.md — each file's access-control note read "SHOW ROUTINE LOAD requires…" regardless of the actual statement. Replaced with the matching statement name in each file.
• CANCEL-LOAD.md — STATE parameter list included FINISHED / CANCELLED, but the syntax + notes only allow PENDING / ETL / LOADING; removed the invalid values. An example used LABEL like "example_" which, without %, doesn't match anything containing example_; changed to "%example_%" to match the prose intent.
• SHOW-LOAD.md — prose said LOAD = "PENDING" where it should say STATE = "PENDING".
• SELECT.md — typo JOIN Exampel → JOIN Example; truncated ome additional knowledge → Some additional knowledge; invalid SQL ORDER by LIMIT 10 → ORDER BY a LIMIT 10; renumbered a duplicated list item 2..
• SHOW-DATABASES.md — Chinese heading ## 示例 in the English doc → ## Examples.
• SHOW-DATABASE-ID.md — ### Description (h3) → ## Description (h2), matching the convention used by sibling docs.
• DROP-FUNCTION.md — syntax DROP [ GLOBAL ] <function_name>(...) was missing the FUNCTION keyword.

Test plan

• CI doc build passes
• Spot-check the affected pages render correctly (Chinese → English headers, link spacing, fixed SQL examples, completed descriptions, h2 headings, FUNCTION keyword in DROP syntax)