Update tesseract man page

- move Tesseract 4 release note to other release notes
- format command line options in text
- add link to release notes (wiki)
- add link to contributors (GitHub)

Signed-off-by: Stefan Weil <sw@weilnetz.de>

doc/tesseract.1.asc

@@ -17,12 +17,6 @@ between 1985 and 1995. In 1995, this engine was among the top 3 evaluated by
 UNLV. It was open-sourced by HP and UNLV in 2005, and has been developed
 at Google since then.
 
-Tesseract 4 adds a new neural net (LSTM) based OCR engine which is focused
-on line recognition, but also still supports the legacy Tesseract OCR engine of 
-Tesseract 3 which works by recognizing character patterns. Compatibility with 
-Tesseract 3 is enabled by --oem 0. It also needs traineddata files which support 
-the legacy engine, for example those from the tessdata repository.
-
 
 IN/OUT ARGUMENTS
 ----------------
@@ -97,7 +91,7 @@ OPTIONS
   * hocr - Output in hOCR format instead of as a text file.
   * pdf  - Output in pdf instead of a text file.
 
-*Nota Bene:*   The options '-l lang' and '--psm N' must occur
+*Nota Bene:*   The options `-l lang` and `--psm N` must occur
 before any 'configfile'.
 
 
@@ -116,7 +110,7 @@ SINGLE OPTIONS
 	Returns the current version of the tesseract(1) executable.
 
 '--list-langs'::
-	List available languages for tesseract engine. Can be used with --tessdata-dir.
+	List available languages for tesseract engine. Can be used with `--tessdata-dir`.
 
 '--print-parameters'::
 	Print tesseract parameters.
@@ -251,7 +245,7 @@ for the following languages are in
 To use a non-standard language pack named *foo.traineddata*, set the
 *TESSDATA_PREFIX* environment variable so the file can be found at
 *TESSDATA_PREFIX*/tessdata/*foo*.traineddata and give Tesseract the
-argument '-l foo'.
+argument `-l foo`.
 
 SCRIPTS
 -------
@@ -377,7 +371,15 @@ language data.
 Tesseract 3.02 adds BiDirectional text support, the ability to recognize
 multiple languages in a single image, and improved layout analysis.
 
-For further details, see the file ReleaseNotes included with the distribution.
+Tesseract 4 adds a new neural net (LSTM) based OCR engine which is focused
+on line recognition, but also still supports the legacy Tesseract OCR engine of
+Tesseract 3 which works by recognizing character patterns. Compatibility with
+Tesseract 3 is enabled by `--oem 0`. It also needs traineddata files which
+support the legacy engine, for example those from the tessdata repository.
+
+For further details, see the file ReleaseNotes in the Tesseract wiki
+(<https://github.com/tesseract-ocr/tesseract/wiki/ReleaseNotes>).
+
 
 RESOURCES
 ---------
@@ -402,6 +404,9 @@ Pingping Xiu, Pong Eksombatchai (Chantat), Ranjith Unnikrishnan, Raquel
 Romano, Ray Smith, Rika Antonova, Robert Moss, Samuel Charron, Sheelagh
 Lloyd, Shobhit Saxena, and Thomas Kielbus.
 
+For a list of contributors see
+<https://github.com/tesseract-ocr/tesseract/blob/master/AUTHORS>.
+
 COPYING
 -------
 Licensed under the Apache License, Version 2.0