SQL: inconsistency between error message for functions

[astefan]

Some functions differ in error messages from others. For example INSERT doesn't mention which parameter should be of a certain type, while REPEAT does:

sql> select insert('aaa','bbb',1,2);
Bad request [Found 1 problem(s)
line 1:8: 'INSERT' requires a numeric type, received keyword]
sql> select repeat(1,2);
Bad request [Found 1 problem(s)
line 1:8: 'REPEAT' requires first parameter to be a string type, received INTEGER]

[elasticmachine]

Pinging @elastic/es-search-aggs