manual: use one-line titles instead of two-line titles (trivial)

Asciidoc supports two syntaxes for section titles: two-line titles (title
plus underline consisting of a particular symbol), and one-line titles
(title prefixed with a specific number of = signs).

The two-line title underlines are:
Level 0 (top level):     ======================
Level 1:                 ----------------------
Level 2:                 ~~~~~~~~~~~~~~~~~~~~~~
Level 3:                 ^^^^^^^^^^^^^^^^^^^^^^
Level 4 (bottom level):  ++++++++++++++++++++++

and the one-line title prefixes:
= Document Title (level 0) =
== Section title (level 1) ==

=== Section title (level 2) ===
==== Section title (level 3) ====
===== Section title (level 4) =====

The buildroot manual is currenly using the two-line titles, but this has
multiple disadvantages:

- asciidoc also uses some of the underline symbols for other purposes (like
  preformatted code, example blocks, ...), which makes it difficult to do
  mass replacements, such as a planned follow-up patch that needs to move
  all sections one level down.

- it is difficult to remember which level a given underline symbol (=-~^+)
  corresponds to, while counting = signs is easy.

This patch changes all two-level titles to one-level titles in the manual.
The bulk of the change was done with the following Python script, except for
the level 1 titles (-----) as these underlines are also used for literal
code blocks.
This patch only changes the titles, no other changes. In
adding-packages-directory.txt, I did add missing newlines between some
titles and their content.

----------------------------------------------------------------------------
#!/usr/bin/env python

import sys
import mmap
import re

for input in sys.argv[1:]:

    f = open(input, 'r+')
    f.flush()
    s = mmap.mmap(f.fileno(), 0)

    # Level 0 (top level):     ======================   =
    # Level 1:                 ----------------------   ==
    # Level 2:                 ~~~~~~~~~~~~~~~~~~~~~~   ===
    # Level 3:                 ^^^^^^^^^^^^^^^^^^^^^^   ====
    # Level 4 (bottom level):  ++++++++++++++++++++++   =====

    def replace_title(s, symbol, replacement):
        pattern = re.compile(r'(.+\n)\%s{2,}\n' % symbol, re.MULTILINE)
        return pattern.sub(r'%s \1' % replacement, s)

    new = s
    new = replace_title(new, '=', '=')
    new = replace_title(new, '+', '=====')
    new = replace_title(new, '^', '====')
    new = replace_title(new, '~', '===')
    #new = replace_title(new, '-', '==')

    s.seek(0)
    s.write(new)
    s.resize(s.tell())
    s.close()
    f.close()

----------------------------------------------------------------------------

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

1 files changed, 11 insertions, 14 deletions

diff --git a/docs/manual/adding-packages-directory.txt b/docs/manual/adding-packages-directory.txt
index 52eb6539db..5d4d5d9f0b 100644
--- a/docs/manual/adding-packages-directory.txt
+++ b/docs/manual/adding-packages-directory.txt
@@ -1,8 +1,7 @@
 // -*- mode:doc; -*-
 // vim: set syntax=asciidoc:
 
-Package directory
-~~~~~~~~~~~~~~~~~
+=== Package directory
 
 First of all, create a directory under the +package+ directory for
 your software, for example +libfoo+.
@@ -13,8 +12,7 @@ one of these categories, then create your package directory in these.
 New subdirectories are discouraged, however.
 
 
-+Config.in+ file
-~~~~~~~~~~~~~~~~
+=== +Config.in+ file
 
 Then, create a file named +Config.in+. This file will contain the
 option descriptions related to our +libfoo+ software that will be used
@@ -52,8 +50,7 @@ source "package/libfoo/Config.in"
 --------------------------
 
 [[depends-on-vs-select]]
-Choosing +depends on+ or +select+
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+==== Choosing +depends on+ or +select+
 
 The +Config.in+ file of your package must also ensure that
 dependencies are enabled. Typically, Buildroot uses the following
@@ -164,8 +161,8 @@ Further formatting details: see xref:writing-rules-config-in[the
 coding style].
 
 [[dependencies-target-toolchain-options]]
-Dependencies on target and toolchain options
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+==== Dependencies on target and toolchain options
+
 Many packages depend on certain options of the toolchain: the choice of
 C library, C++ support, largefile support, thread support, RPC support,
 IPv6 support, wchar support, or dynamic library support. Some packages
@@ -268,8 +265,8 @@ use in the comment.
 ** Dependency symbol: +!BR2_PREFER_STATIC_LIB+
 ** Comment string: +dynamic library+
 
-Dependencies on a Linux kernel built by buildroot
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+==== Dependencies on a Linux kernel built by buildroot
+
 Some packages need a Linux kernel to be built by buildroot. These are
 typically kernel modules or firmware. A comment should be added in the
 Config.in file to express this dependency, similar to dependencies on
@@ -285,8 +282,8 @@ kernel, use this format:
 foo needs a toolchain w/ featA, featB, featC and a Linux kernel to be built
 --------------------------
 
-Dependencies on udev /dev management
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+==== Dependencies on udev /dev management
+
 If a package needs udev /dev management, it should depend on symbol
 +BR2_PACKAGE_HAS_UDEV+, and the following comment should be added:
 
@@ -301,8 +298,8 @@ management, use this format:
 foo needs udev /dev management and a toolchain w/ featA, featB, featC
 --------------------------
 
-The +.mk+ file
-~~~~~~~~~~~~~~
+=== The +.mk+ file
+
 [[adding-packages-mk]]
 
 Finally, here's the hardest part. Create a file named +libfoo.mk+. It