README: create HTTP/HTTPS links from URLs in Markdown

Markdown supports automatic links by surrounding URLs with
angle brackets, as documented in
<https://daringfireball.net/projects/markdown/syntax#autolink>

While we're at it, update URLs to avoid redirecting clients for
git-scm.com (by using HTTPS) and public-inbox.org (by adding a
trailing slash).

Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

README.md

@@ -12,7 +12,7 @@ Torvalds with help of a group of hackers around the net.
 
 Please read the file [INSTALL][] for installation instructions.
 
-Many Git online resources are accessible from http://git-scm.com/
+Many Git online resources are accessible from <https://git-scm.com/>
 including full documentation and Git related tools.
 
 See [Documentation/gittutorial.txt][] to get started, then see
@@ -33,8 +33,8 @@ requests, comments and patches to git@vger.kernel.org (read
 [Documentation/SubmittingPatches][] for instructions on patch submission).
 To subscribe to the list, send an email with just "subscribe git" in
 the body to majordomo@vger.kernel.org. The mailing list archives are
-available at https://public-inbox.org/git,
-http://marc.info/?l=git and other archival sites.
+available at <https://public-inbox.org/git/>,
+<http://marc.info/?l=git> and other archival sites.
 
 The maintainer frequently sends the "What's cooking" reports that
 list the current status of various development topics to the mailing