Fix weird formatting of html manpage

Asciidoc was inserting <pre> tags for paragraphs that started with a
'+' at the beginning of the line. Instead, we need a space in front of
the plus.

doc/tor.1.txt

@@ -509,14 +509,14 @@ The following options are useful only for clients (that is, if
     patterns of nodes to avoid when building a circuit.
     (Example:
     ExcludeNodes SlowServer, $    EFFFFFFFFFFFFFFF, \{cc}, 255.254.0.0/8) +
-+
+ +
     By default, this option is treated as a preference that Tor is allowed
     to override in order to keep working.
     For example, if you try to connect to a hidden service,
     but you have excluded all of the hidden service's introduction points,
     Tor will connect to one of them anyway.  If you do not want this
     behavior, set the StrictNodes option (documented below).  +
-+
+ +
     Note also that if you are a relay, this (and the other node selection
     options below) only affects your own circuits that Tor builds for you.
     Clients can still build circuits through you to any node.  Controllers
@@ -535,22 +535,22 @@ The following options are useful only for clients (that is, if
     A list of identity fingerprints, nicknames, country codes and address
     patterns of nodes to use as exit node---that is, a
     node that delivers traffic for you outside the Tor network. +
-+
+ +
     Note that if you list too few nodes here, or if you exclude too many exit
     nodes with ExcludeExitNodes, you can degrade functionality.  For example,
     if none of the exits you list allows traffic on port 80 or 443, you won't
     be able to browse the web. +
-+
+ +
     Note also that not every circuit is used to deliver traffic outside of
     the Tor network.  It is normal to see non-exit circuits (such as those
     used to connect to hidden services, those that do directory fetches,
     those used for relay reachability self-tests, and so on) that end
     at a non-exit node.  To
     keep a node from being used entirely, see ExcludeNodes and StrictNodes. +
-+
+ +
     The ExcludeNodes option overrides this option: any node listed in both
     ExitNodes and ExcludeNodes is treated as excluded. +
-+
+ +
     The .exit address notation, if enabled via AllowDotExit, overrides
     this option.
 
@@ -561,7 +561,7 @@ The following options are useful only for clients (that is, if
     circuits except for direct connections to directory servers.  The Bridge
     option overrides this option; if you have configured bridges and
     UseBridges is 1, the Bridges are used as your entry nodes. +
-+
+ +
     The ExcludeNodes option overrides this option: any node listed in both
     EntryNodes and ExcludeNodes is treated as excluded.