Cleanups in gen_licenses.py

Changes include:

- Using asciidoctor's heading style

- (Issue 4424) Add extra \n before closing blockquote so that an
imported LICENSE file without \n at the end won't screw up the rest of
the file

- Change the license anchor to something more distinguishable

- Use '----' instead of '[verse]\n--' for license blockquote, as we have
some hack inside lib/LICENSE-prologcafe using '----' as blockquote.
We could also just change lib/LICENSE-prologcafe file to use '--'
instead, but I feel under asciidoctor's default css, '----' blockquotes
has a slightly grey background, which is easier to read.

Change-Id: I8260c47ffa66cd303b97f78c590cdfd97a8626d4

Documentation/gen_licenses.py

@@ -95,16 +95,14 @@ used = sorted(licenses.keys())
 
 if args.asciidoc:
   print("""\
-Gerrit Code Review - Licenses
-=============================
+= Gerrit Code Review - Licenses
 
 Gerrit open source software is licensed under the <<Apache2_0,Apache
 License 2.0>>.  Executable distributions also include other software
 components that are provided under additional licenses.
 
 [[cryptography]]
-Cryptography Notice
--------------------
+== Cryptography Notice
 
 This distribution includes cryptographic software.  The country
 in which you currently reside may have restrictions on the import,
@@ -139,8 +137,7 @@ and/or the
 link:http://www.bouncycastle.org/java.html[Bouncy Castle Crypto API]
 to be installed by the end-user.
 
-Licenses
---------
+== Licenses
 """)
 
 for n in used:
@@ -149,13 +146,13 @@ for n in used:
   if args.asciidoc:
     print()
     print('[[%s]]' % name.replace('.', '_'))
-    print(name)
-    print('~' * len(name))
+    print("=== " + name)
     print()
   else:
     print()
     print(name)
-    print('--')
+    print()
+    print('----')
   for d in libs:
     if d.startswith('//lib:') or d.startswith('//lib/'):
       p = d[len('//lib:'):]
@@ -166,12 +163,12 @@ for n in used:
     print('* ' + p)
   if args.asciidoc:
     print()
-    print('[[license]]')
-    print('[verse]')
-    print('--')
+    print('[[%s_license]]' % name.replace('.', '_'))
+    print('----')
   with open(n[2:].replace(':', '/')) as fd:
     copyfileobj(fd, stdout)
-  print('--')
+  print()
+  print('----')
 
 if args.asciidoc:
   print("""