runtime(doc): Fix manpage typo in description of '--ttyfail'

This seems to have been accidentally introduced in
ce6fe84db2.

closes: #20186

Signed-off-by: Matthew Fernandez <matthew.fernandez@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/vim.1

@@ -515,7 +515,7 @@ GTK GUI only: Use the GtkPlug mechanism to run gVim in another window.
 During startup write timing messages to the file {fname}.
 .TP
 \-\-ttyfail
-When stdin or stdout is not a a terminal (tty) then exit right away.
+When stdin or stdout is not a terminal (tty) then exit right away.
 .TP
 \-\-version
 Print version information and exit.

runtime/doc/vim.man

@@ -396,7 +396,7 @@ OPTIONS
        --startuptime {file}
                    During startup write timing messages to the file {fname}.
 
-       --ttyfail   When  stdin  or  stdout is not a a terminal (tty) then exit
+       --ttyfail   When  stdin  or  stdout is not a terminal (tty) then exit
                    right away.
 
        --version   Print version information and exit.