Merge branch 'document_--version'

changes/document_version

+  o Documentation:
+    - Document the exact output of "tor --version". Closes ticket 28889.

doc/tor.1.txt

@@ -89,7 +89,9 @@ COMMAND-LINE OPTIONS
     future version. (This is a warning, not a promise.)
 
 [[opt-version]] **--version**::
-    Display Tor version and exit.
+    Display Tor version and exit. The output is a single line of the format
+    "Tor version [version number]."  (The version number format
+    is as specified in version-spec.txt.)
 
 [[opt-quiet]] **--quiet**|**--hush**::
     Override the default console log.  By default, Tor starts out logging