koma-letter-export.org: Add fromlogo documentation.

exporters/koma-letter-export.org

@@ -313,6 +313,7 @@ lines. In general, they correspond to a LaTeX command such as:
 | Option line     | Emacs variable                    | KOMA-Script variable | Description                                      |
 |-----------------+-----------------------------------+----------------------+--------------------------------------------------|
 | =#+LCO:=          | =org-koma-letter-class-option-file= |                      | The default LCO file.                            |
+| =#+FROM_LOGO=     | =org-koma-letter-from-logo=         | =fromlogo=             | The sender's logo.                               |
 | =#+TITLE:=        |                                   | =title=                | The  title of the letter.                        |
 | =#+SUBJECT:=      |                                   | =subject=              | The subject of the letter                        |
 | =#+DATE:=         |                                   | =date=                 | The time-stamp of the letter.                    |
@@ -352,6 +353,7 @@ general, they correspond to a LaTeX command such as:
 | =foldmarks=           | =org-koma-letter-use-foldmarks=              | =foldmarks=          | If and how foldmarks are printed.                                    |
 | =subject=             | =org-koma-letter-subject-format=             | =subject=            | If and how to print the letter's subject line.                       |
 | =place=               | =org-koma-letter-use-place=                  |                    | Print the letter's place stamp.                                      |
+| =from-logo=           | =org-koma-letter-use-from-logo=              | =fromlogo=           | Insert the sender's logo.                                            |
 
 *** DONE List of =ox-koma-letter= special headings
 :PROPERTIES: