Replace the hardcoded "me" stamp for outgoing messages that are
sometimes used with the value from PREF_OUTGOING_STAMP.
It was never implemented in all code paths. Like with receipts for
example.
Additionally fix the confusing description and variable names.
Ref: 2c003dd2 (Add /stamp feature)
Ref: 3a4cd7da (Broke the variables)
Fixes: https://github.com/profanity-im/profanity/issues/2125
Signed-off-by: Michael Vetter <jubalh@iodoru.org>
b0a89530f2