Merge pull request #622 from w3f/update-extra-signed

Update Extrinsic Signature description

02_runtime/07-extrinsics.adoc

@@ -107,14 +107,17 @@ where::
 * latexmath:[M_i]: the module indicator (<<defn-module-indicator>>).
 * latexmath:[F_i(m)]: the function indicator of the module (<<defn-function-indicator>>).
 * latexmath:[E]: the extra data (<<defn-extra-data>>).
-* latexmath:[R_v]: a UINT32 containing the specification version of `14`.
-* latexmath:[F_v]: a UINT32 containing the format version of `2`.
+* latexmath:[R_v]: a UINT32 containing the specification version
+(`spec_version`) of the Runtime (<<#defn-rt-core-version>>), which can be
+updated and is therefore subject to change.
+* latexmath:[F_v]: a UINT32 containing the transaction version
+(`transaction_version`) of the Runtime (<<#defn-rt-core-version>>), which can be
+updated and is therefore subject to change.
 * latexmath:[H_h(G)]: a 32-byte array containing the genesis hash.
 * latexmath:[H_h(B)]: a 32-byte array containing the hash of the block
 which starts the mortality period, as described in <<defn-extrinsic-mortality>>.
 ====
 
-
 .Extra Data
 [#defn-extra-data]
 ====