Added missing spec for calculating message size using given name and clientId

Author: sacOO7

textile/features.textile

@@ -1454,6 +1454,8 @@ h4. Message
 ** @(TM6b)@ The size of an @Object@ or @Array@ @data@ property is its string length after being JSON-stringified
 ** @(TM6c)@ The size of a @binary@ @data@ property is its size in bytes (of the actual binary, not the base64 representation, regardless of whether the binary protocol is in use)
 ** @(TM6f)@ The size of a @string@ @data@ property is its length
+** @(TM6g)@ The size of a @string@ @name@ property is its length
+** @(TM6h)@ The size of a @string@ @clientId@ property is its length
 ** @(TM6d)@ The size of the @extras@ property is the string length of its JSON representation
 ** @(TM6e)@ The size of a @null@ or omitted property is zero
 * @(TM7)@ The SDK may expose a series of functions (static factory methods on a Message or otherwise, wherever is language idiomatic; for some languages this might just be types that can be used for type assertions, etc), that take a deserialized @JsonObject@, one of the aggregated summaries for a particular annotation type (that is, a value from the @TM2q@ @summary@ @Dict@), and outputs a strongly-typed summary entry, for ease of use by the end user (particularly in languages where manipulating plain objects is difficult).