Update data types

We have a new flat array type

Author: ohsayan

docs/protocol/data-types.md

@@ -10,13 +10,15 @@ type symbols ( `tsymbol` s) and additional information.
 |--|--|--|
 |+|String|the next line is a string|
 |!|Response Code|the next line is a response code|
+|&|Array|Arrays that can be recursive|
+|_|Flat array|An array that only has strings|
 |$|JSON|the next line is a `JSON` value|
-|-|smallint|An integer in the range: [0, 255]|
-|_|smallint signed|An integer in the range: [-128, 127]|
+|.|smallint|An integer in the range: [0, 255]|
+|-|smallint signed|An integer in the range: [-128, 127]|
 |:|int|An integer in the range: [0, 4,294,967,295]|
 |;|int signed|An integer in the range: [-2,147,483,647, 2,147,483,647]|
 |%|float|A 32-bit floating point value|
 |?|binary|the next line contains binary data (often called a blob)|
 
 
-Do keep the matching for this symbol _non-exhaustive_ since we might add more types in future revisions of the protocol.
+Do keep the matching for this symbol _non-exhaustive_ since we might add more types in future revisions of the protocol.