docs: ARC: Improve readability

There were some things which made rendered document
look not very elegant. That was because:

1. Numbered lists were formatted in more of Markdown way
   rather than true reStructuredText and so were displayed
   as a plain text with leading numbers.

   Well, moreover numbered lists were not needed as in all cases
   we were just listing a couple of options w/o any intention to
   follow any particular order, so a simpler unordered list fits
   better and looks cleaner.

2. URL's of external resources were added as they are
   (which is OK in a plain text, but make not much sense in
   a HTML where we may use more human-friendly link names
   with URL's hidden.

3. Some URL's had trailing slashes which were not really needed

Fix all items from above!

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Vineet Gupta <vgupta@kernel.org>
Link: https://lore.kernel.org/r/20211202215747.19923-1-abrodkin@synopsys.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/arc/arc.rst

@@ -9,24 +9,27 @@ Other sources of information
 Below are some resources where more information can be found on
 ARC processors and relevant open source projects.
 
-1. `<https://embarc.org/>`_ - Community portal for open source on ARC.
+- `<https://embarc.org>`_ - Community portal for open source on ARC.
   Good place to start to find relevant FOSS projects, toolchain releases,
   news items and more.
 
-2. `<https://github.com/foss-for-synopsys-dwc-arc-processors>`_ -
+- `<https://github.com/foss-for-synopsys-dwc-arc-processors>`_ -
   Home for all development activities regarding open source projects for
   ARC processors. Some of the projects are forks of various upstream projects,
   where "work in progress" is hosted prior to submission to upstream projects.
   Other projects are developed by Synopsys and made available to community
   as open source for use on ARC Processors.
 
-3. `<https://www.synopsys.com/designware-ip/processor-solutions.html>`_ -
-Official Synopsys ARC Processors website location, with access to some IP
-documentation (Programmer's Reference Manuals, AKA "PRM's", see
-`<https://www.synopsys.com/dw/doc.php/ds/cc/programmers-reference-manual-ARC-HS.pdf>`_)
-and commercial tools (Free nSIM,
-`<https://www.synopsys.com/cgi-bin/dwarcnsim/req1.cgi>`_ and
-MetaWare Light Edition, `<https://www.synopsys.com/cgi-bin/arcmwtk_lite/reg1.cgi>`_)
+- `Official Synopsys ARC Processors website
+  <https://www.synopsys.com/designware-ip/processor-solutions.html>`_ -
+  location, with access to some IP documentation (`Programmer's Reference
+  Manual, AKA PRM for ARC HS processors
+  <https://www.synopsys.com/dw/doc.php/ds/cc/programmers-reference-manual-ARC-HS.pdf>`_)
+  and free versions of some commercial tools (`Free nSIM
+  <https://www.synopsys.com/cgi-bin/dwarcnsim/req1.cgi>`_ and
+  `MetaWare Light Edition <https://www.synopsys.com/cgi-bin/arcmwtk_lite/reg1.cgi>`_).
+  Please note though, registration is required to access both the documentation and
+  the tools.
 
 Important note on ARC processors configurability
 ################################################
@@ -52,10 +55,9 @@ Building the Linux kernel for ARC processors
 The process of kernel building for ARC processors is the same as for any other
 architecture and could be done in 2 ways:
 
-1. cross-compilation: process of compiling for ARC targets on a development
+- Cross-compilation: process of compiling for ARC targets on a development
   host with a different processor architecture (generally x86_64/amd64).
-
-2. native compilation: process of compiling for ARC on a ARC platform
+- Native compilation: process of compiling for ARC on a ARC platform
   (hardware board or a simulator like QEMU) with complete development environment
   (GNU toolchain, dtc, make etc) installed on the platform.
 
@@ -63,11 +65,13 @@ In both cases, up-to-date GNU toolchain for ARC for the host is needed.
 Synopsys offers prebuilt toolchain releases which can be used for this purpose,
 available from:
 
-1. Synopsys GNU toolchain releases:
+- Synopsys GNU toolchain releases:
   `<https://github.com/foss-for-synopsys-dwc-arc-processors/toolchain/releases>`_
-2. Linux kernel compilers collection:
-`<https://mirrors.edge.kernel.org/pub/tools/crosstool/>`_
-3. Bootlin's toolchain collection: `<https://toolchains.bootlin.com/>`_
+
+- Linux kernel compilers collection:
+  `<https://mirrors.edge.kernel.org/pub/tools/crosstool>`_
+
+- Bootlin's toolchain collection: `<https://toolchains.bootlin.com>`_
 
 Once the toolchain is installed in the system, make sure its "bin" folder
 is added in your ``PATH`` environment variable. Then set ``ARCH=arc`` &