[FAB-9260] Remove trailing whitespace in docs rst files

Git whines about trailing whitespace in text files, so remove
that from a small number of docs/source/*.rst files. That
includes making sure blank lines are truly empty lines, not
just lines with nothing but blanks.

Change-Id: I8a2c095e92af8d0777818d743cdacd2f044be6b4
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>

Author: rpjday

docs/source/arch-deep-dive.rst

@@ -99,7 +99,7 @@ More formally, state ``s`` is modeled as an element of a mapping
    next version number.
 
 Both ``V`` and ``N`` contain a special element |falsum| (empty type), which is
-in case of ``N`` the lowest element. Initially all keys are mapped to 
+in case of ``N`` the lowest element. Initially all keys are mapped to
 (|falsum|, |falsum|). For ``s(k)=(v,ver)`` we denote ``v`` by ``s(k).value``,
 and ``ver`` by ``s(k).version``.
 

docs/source/chaincode4ade.rst

@@ -11,9 +11,9 @@ the endorsing peer process. Chaincode initializes and manages the ledger state
 through transactions submitted by applications.
 
 A chaincode typically handles business logic agreed to by members of the
-network, so it similar to a "smart contract". A chaincode can be invoked to update or query 
-the ledger in a proposal transaction. Given the appropriate permission, a chaincode 
-may invoke another chaincode, either in the same channel or in different channels, to access its state. 
+network, so it similar to a "smart contract". A chaincode can be invoked to update or query
+the ledger in a proposal transaction. Given the appropriate permission, a chaincode
+may invoke another chaincode, either in the same channel or in different channels, to access its state.
 Note that, if the called chaincode is on a different channel from the calling chaincode,
 only read query is allowed. That is, the called chaincode on a different channel is only a `Query`,
 which does not participate in state validation checks in subsequent commit phase.