Fix torrc-format documentation corner cases

We don't require that the final line be terminated, and we open
windows torrc files in text mode.

Closes ticket 22795.

doc/torrc_format.txt

@@ -18,9 +18,10 @@ does, not what it should do.
    ; specified in RFC5234.
 
    ; A file is interpreted as every Entry in the file, in order.
-   TorrcFile = *Line
+   TorrcFile = *Line [ UnterminatedLine ]
 
-   Line = BlankLine / Entry
+   Line = BlankLine LF / Entry LF
+   UnterminatedLine = BlankLine / Entry
 
    BlankLine =  *WSP OptComment LF
    BlankLine =/ *WSP LF
@@ -69,6 +70,12 @@ does, not what it should do.
    ; Anything besides NUL and LF
    NonLF = %x01-%x09 / %x0b - %xff
 
+   ; Note that on windows, we open our configuration files in "text" mode,
+   ; which causes CRLF pairs to be interpreted as LF.  So, on windows:
+   ;         LF = [ %x0d ] %x0a
+   ; but everywhere else,
+   LF = %0x0a
+
    OCTDIG = '0' - '7'
 
    KC = Any character except an isspace() character or '#' or NUL