[Doc] Repair document format (#4336)

The error format '##keyword' in a lot of docs. This pr is to repair document format. #4335

docs/en/sql-reference/sql-functions/string-functions/ascii.md

@@ -50,5 +50,5 @@ mysql> select ascii('234');
 |           50 |
 +--------------+
 ```
-##keyword
+## keyword
 ASCII

docs/en/sql-reference/sql-functions/string-functions/concat.md

@@ -57,5 +57,5 @@ mysql> select concat("a", null, "c");
 | NULL                   |
 +------------------------+
 ```
-##keyword
+## keyword
 CONCAT

docs/en/sql-reference/sql-functions/string-functions/concat_ws.md

@@ -59,5 +59,5 @@ mysql> select concat_ws("or", "d", NULL,"is");
 | doris                           |
 +---------------------------------+
 ```
-##keyword
+## keyword
 CONCAT_WS,CONCAT,WS

docs/en/sql-reference/sql-functions/string-functions/ends_with.md

@@ -50,5 +50,5 @@ mysql> select ends_with("Hello doris", "Hello");
 |                                 0 | 
 +-----------------------------------+
 ```
-##keyword
+## keyword
 ENDS_WITH

docs/en/sql-reference/sql-functions/string-functions/find_in_set.md

@@ -45,5 +45,5 @@ mysql> select find_in_set("b", "a,b,c");
 |                         2 |
 +---------------------------+
 ```
-##keyword
+## keyword
 FIND_IN_SET,FIND,IN,SET

docs/en/sql-reference/sql-functions/string-functions/get_json_double.md

@@ -70,5 +70,5 @@ mysql> SELECT get_json_double('{"k1.key":{"k2":[1.1, 2.2]}}', '$."k1.key".k2[0]'
 |                                                                 1.1 |
 +---------------------------------------------------------------------+
 ```
-##keyword
+## keyword
 GET_JSON_DOUBLE,GET,JSON,DOUBLE

docs/en/sql-reference/sql-functions/string-functions/get_json_int.md

@@ -70,5 +70,5 @@ mysql> SELECT get_json_int('{"k1.key":{"k2":[1, 2]}}', '$."k1.key".k2[0]');
 |                                                            1 |
 +--------------------------------------------------------------+
 ```
-##keyword
+## keyword
 GET_JSON_INT,GET,JSON,INT

docs/en/sql-reference/sql-functions/string-functions/get_json_string.md

@@ -80,5 +80,5 @@ mysql> SELECT get_json_string('[{"k1":"v1"}, {"k2":"v2"}, {"k1":"v3"}, {"k1":"v4
 | ["v1","v3","v4"]                                                                |
 +---------------------------------------------------------------------------------+
 ```
-##keyword
+## keyword
 GET_JSON_STRING,GET,JSON,STRING

docs/en/sql-reference/sql-functions/string-functions/group_concat.md

@@ -59,5 +59,5 @@ mysql> select group_concat(value, " ") from test;
 | a b c                      |
 +----------------------------+
 ```
-##keyword
+## keyword
 GROUP_CONCAT,GROUP,CONCAT

docs/en/sql-reference/sql-functions/string-functions/instr.md

@@ -50,5 +50,5 @@ mysql> select instr("abc", "d");
 |                 0 |
 +-------------------+
 ```
-##keyword
+## keyword
 INSTR

docs/en/sql-reference/sql-functions/string-functions/lcase.md

@@ -33,5 +33,5 @@ under the License.
 
 Consistent with `lower`.
 
-##keyword
+## keyword
 LCASE

docs/en/sql-reference/sql-functions/string-functions/left.md

@@ -43,5 +43,5 @@ mysql> select left("Hello doris",5);
 | Hello                  |
 +------------------------+
 ```
-##keyword
+## keyword
 LEFT

docs/en/sql-reference/sql-functions/string-functions/length.md

@@ -50,5 +50,5 @@ mysql> select length("中国");
 |                6 |
 +------------------+
 ```
-##keyword
+## keyword
 LENGTH

docs/en/sql-reference/sql-functions/string-functions/locate.md

@@ -57,5 +57,5 @@ mysql> SELECT LOCATE('bar', 'foobarbar', 5);
 |                             7 |
 +-------------------------------+
 ```
-##keyword
+## keyword
 LOCATE

docs/en/sql-reference/sql-functions/string-functions/lower.md

@@ -43,5 +43,5 @@ mysql> SELECT lower("AbC123");
 | abc123          |
 +-----------------+
 ```
-##keyword
+## keyword
 LOWER

docs/en/sql-reference/sql-functions/string-functions/lpad.md

@@ -50,5 +50,5 @@ mysql> SELECT lpad("hi", 1, "xy");
 | h                   |
 +---------------------+
 ```
-##keyword
+## keyword
 LPAD

docs/en/sql-reference/sql-functions/string-functions/ltrim.md

@@ -43,5 +43,5 @@ mysql> SELECT ltrim('   ab d');
 | ab d             |
 +------------------+
 ```
-##keyword
+## keyword
 LTRIM

docs/en/sql-reference/sql-functions/string-functions/money_format.md

@@ -57,5 +57,5 @@ mysql> select money_format(1123.4);
 | 1,123.40             |
 +----------------------+
 ```
-##keyword
+## keyword
 MONEY_FORMAT,MONEY,FORMAT

docs/en/sql-reference/sql-functions/string-functions/null_or_empty.md

@@ -56,5 +56,5 @@ MySQL [(none)]> select null_or_empty("a");
 |                  0 |
 +--------------------+
 ```
-##keyword
+## keyword
 NULL_OR_EMPTY

docs/en/sql-reference/sql-functions/string-functions/regexp_extract.md

@@ -50,5 +50,5 @@ mysql> SELECT regexp_extract('AbCdE', '([[:lower:]]+)C([[:lower:]]+)', 2);
 | d                                                           |
 +-------------------------------------------------------------+
 ```
-##keyword
+## keyword
 REGEXP_EXTRACT,REGEXP,EXTRACT

docs/en/sql-reference/sql-functions/string-functions/regexp_replace.md

@@ -50,5 +50,5 @@ mysql> SELECT regexp_replace('a b c','(b)','<\\1>');
 | a <b> c                                |
 +----------------------------------------+
 ```
-##keyword
+## keyword
 REGEXP_REPLACE,REGEXP,REPLACE

docs/en/sql-reference/sql-functions/string-functions/repeat.md

@@ -50,5 +50,5 @@ mysql> SELECT repeat("a", -1);
 |                 |
 +-----------------+
 ```
-##keyword
+## keyword
 REPEAT,

docs/en/sql-reference/sql-functions/string-functions/right.md

@@ -43,5 +43,5 @@ mysql> select right("Hello doris",5);
 | doris                   |
 +-------------------------+
 ```
-##keyword
+## keyword
 RIGHT

docs/en/sql-reference/sql-functions/string-functions/rpad.md

@@ -50,5 +50,5 @@ mysql> SELECT rpad("hi", 1, "xy");
 | h                   |
 +---------------------+
 ```
-##keyword
+## keyword
 RPAD

docs/en/sql-reference/sql-functions/string-functions/split_part.md

@@ -65,5 +65,5 @@ mysql> select split_part("abca", "a", 1);
 |                            |
 +----------------------------+
 ```
-##keyword
+## keyword
 SPLIT_PART,SPLIT,PART

docs/en/sql-reference/sql-functions/string-functions/starts_with.md

@@ -50,5 +50,5 @@ MySQL [(none)]> select starts_with("hello world","world");
 |                                   0 |
 +-------------------------------------+
 ```
-##keyword
+## keyword
 STARTS_WITH

docs/en/sql-reference/sql-functions/string-functions/strleft.md

@@ -43,5 +43,5 @@ mysql> select strleft("Hello doris",5);
 | Hello                  |
 +------------------------+
 ```
-##keyword
+## keyword
 STRLEFT

docs/en/sql-reference/sql-functions/string-functions/strright.md

@@ -44,5 +44,5 @@ mysql> select strright("Hello doris",5);
 | doris                   |
 +-------------------------+
 ```
-##keyword
+## keyword
 STRRIGHT