tools: add sql-mode config for sync-diff-inspector (#1650)

Author: junlan-zhang

dev/reference/tools/sync-diff-inspector/overview.md

@@ -185,6 +185,8 @@ fix-sql-file = "fix.sql"
     # Uses the snapshot function of TiDB.
     # If enabled, the history data is used for comparison.
     # snapshot = "2016-10-08 16:45:26"
+    # Sets the `sql-mode` of the database to parse table structures.
+    # sql-mode = ""
 
 # Configuration of the target database instance
 [target-db]
@@ -195,6 +197,8 @@ fix-sql-file = "fix.sql"
     # Uses the snapshot function of TiDB.
     # If enabled, the history data is used for comparison.
     # snapshot = "2016-10-08 16:45:26"
+    # Sets the `sql-mode` of the database to parse table structures.
+    # sql-mode = ""
 ```
 
 ### Run sync-diff-inspector

v2.1/reference/tools/sync-diff-inspector/overview.md

@@ -186,6 +186,8 @@ fix-sql-file = "fix.sql"
     # Uses the snapshot function of TiDB.
     # If enabled, the history data is used for comparison.
     # snapshot = "2016-10-08 16:45:26"
+    # Sets the `sql-mode` of the database to parse table structures.
+    # sql-mode = ""
 
 # Configuration of the target database instance
 [target-db]
@@ -196,6 +198,8 @@ fix-sql-file = "fix.sql"
     # Uses the snapshot function of TiDB.
     # If enabled, the history data is used for comparison.
     # snapshot = "2016-10-08 16:45:26"
+    # Sets the `sql-mode` of the database to parse table structures.
+    # sql-mode = ""
 ```
 
 ### Run sync-diff-inspector

v3.0/reference/tools/sync-diff-inspector/overview.md

@@ -186,6 +186,8 @@ fix-sql-file = "fix.sql"
     # Uses the snapshot function of TiDB.
     # If enabled, the history data is used for comparison.
     # snapshot = "2016-10-08 16:45:26"
+    # Sets the `sql-mode` of the database to parse table structures.
+    # sql-mode = ""
 
 # Configuration of the target database instance
 [target-db]
@@ -196,6 +198,8 @@ fix-sql-file = "fix.sql"
     # Uses the snapshot function of TiDB.
     # If enabled, the history data is used for comparison.
     # snapshot = "2016-10-08 16:45:26"
+    # Sets the `sql-mode` of the database to parse table structures.
+    # sql-mode = ""
 ```
 
 ### Run sync-diff-inspector

v3.1/reference/tools/sync-diff-inspector/overview.md

@@ -185,6 +185,8 @@ fix-sql-file = "fix.sql"
     # Uses the snapshot function of TiDB.
     # If enabled, the history data is used for comparison.
     # snapshot = "2016-10-08 16:45:26"
+    # Sets the `sql-mode` of the database to parse table structures.
+    # sql-mode = ""
 
 # Configuration of the target database instance
 [target-db]
@@ -195,6 +197,8 @@ fix-sql-file = "fix.sql"
     # Uses the snapshot function of TiDB.
     # If enabled, the history data is used for comparison.
     # snapshot = "2016-10-08 16:45:26"
+    # Sets the `sql-mode` of the database to parse table structures.
+    # sql-mode = ""
 ```
 
 ### Run sync-diff-inspector