Add Solidity to programming languages

[issanyo]

Tested locally:

$ scripts/scan_for_anomalies.sh -t train_sol -d example_repo  -o results_sol -l 5 
$ ll train_sol 
-rw-r--r--  1 admin  staff  1421383 Oct  6 09:38 train_sol

train_sol:

0,AST_expression_TWO:(condition_clause (binary_expression ("!=") (non_terminal_expression) (non_terminal_expression)))
//(allowance[from][msg.sender] != uint(-1))
0,AST_expression_ONE:(condition_clause (binary_expression ("!=") (subscript_expression (subscript_expression (identifier)(identifier))(field_expression (identifier)(field_identifier)))(call_expression (identifier)(argument_list (number_literal)))))
0,AST_expression_TWO:(condition_clause (binary_expression ("!=") (non_terminal_expression) (non_terminal_expression)))
//(blockTimestampLast != blockTimestamp)
0,AST_expression_ONE:(condition_clause (binary_expression ("!=") (identifier)(identifier)))
0,AST_expression_TWO:(condition_clause (binary_expression ("!=") (identifier) (identifier)))
//(leftSide < rightSide)
0,AST_expression_ONE:(condition_clause (binary_expression ("<") (identifier)(identifier)))
0,AST_expression_TWO:(condition_clause (binary_expression ("<") (identifier) (identifier)))
//(amountIn == 0)
0,AST_expression_ONE:(condition_clause (binary_expression ("==") (identifier)(number_literal)))
0,AST_expression_TWO:(condition_clause (binary_expression ("==") (identifier) (number_literal)))
.....