docs: use https for some links (#2051)

README.rst

@@ -318,7 +318,7 @@ Projects using this library
 * `ClickHouse <https://github.com/ClickHouse/ClickHouse>`_: analytical database
   management system
 
-* `CUAUV <http://cuauv.org/>`_: Cornell University's autonomous underwater
+* `CUAUV <https://cuauv.org/>`_: Cornell University's autonomous underwater
   vehicle
 
 * `Drake <https://drake.mit.edu/>`_: a planning, control, and analysis toolbox

doc/api.rst

@@ -33,7 +33,7 @@ include ``fmt/format.h`` instead of ``fmt/core.h``.
 
 The following functions use :ref:`format string syntax <syntax>`
 similar to that of Python's `str.format
-<http://docs.python.org/3/library/stdtypes.html#str.format>`_.
+<https://docs.python.org/3/library/stdtypes.html#str.format>`_.
 They take *format_str* and *args* as arguments.
 
 *format_str* is a format string that contains literal text and replacement
@@ -498,7 +498,7 @@ user-defined types that have overloaded ``operator<<``::
 
 The header ``fmt/printf.h`` provides ``printf``-like formatting functionality.
 The following functions use `printf format string syntax
-<http://pubs.opengroup.org/onlinepubs/009695399/functions/fprintf.html>`_ with
+<https://pubs.opengroup.org/onlinepubs/009695399/functions/fprintf.html>`_ with
 the POSIX extension for positional arguments. Unlike their standard
 counterparts, the ``fmt`` functions are type-safe and throw an exception if an
 argument type doesn't match its format specification.

doc/index.rst

@@ -26,7 +26,7 @@ is safer, simpler and several times `faster
 <https://www.zverovich.net/2020/06/13/fast-int-to-string-revisited.html>`_
 than common standard library implementations.
 The `format string syntax <syntax.html>`_ is similar to the one used by
-`str.format <http://docs.python.org/3/library/stdtypes.html#str.format>`_ in
+`str.format <https://docs.python.org/3/library/stdtypes.html#str.format>`_ in
 Python:
 
 .. code:: c++
@@ -197,6 +197,6 @@ using the library both in open-source and commercial projects.
   <a class="btn btn-success" href="https://github.com/fmtlib/fmt">GitHub Repository</a>
 
   <div class="section footer">
-    <iframe src="http://ghbtns.com/github-btn.html?user=fmtlib&amp;repo=fmt&amp;type=watch&amp;count=true"
+    <iframe src="https://ghbtns.com/github-btn.html?user=fmtlib&amp;repo=fmt&amp;type=watch&amp;count=true"
             class="github-btn" width="100" height="20"></iframe>
   </div>

doc/syntax.rst

@@ -353,7 +353,7 @@ Specifiers that have a calendaric component such as `'d'` (the day of month)
 are valid only for ``std::tm`` and not durations or time points.
 
 ``std::tm`` uses the system's `strftime
-<http://en.cppreference.com/w/cpp/chrono/c/strftime>`_ so refer to its
+<https://en.cppreference.com/w/cpp/chrono/c/strftime>`_ so refer to its
 documentation for details on supported conversion specifiers. 
 
 .. _formatexamples:

doc/usage.rst

@@ -15,7 +15,7 @@ Building the Library
 
 The included `CMake build script`__ can be used to build the fmt
 library on a wide range of platforms. CMake is freely available for
-download from http://www.cmake.org/download/.
+download from https://www.cmake.org/download/.
 
 __ https://github.com/fmtlib/fmt/blob/master/CMakeLists.txt
 
@@ -50,7 +50,7 @@ To build a `shared library`__ set the ``BUILD_SHARED_LIBS`` CMake variable to
 
   cmake -DBUILD_SHARED_LIBS=TRUE ...
 
-__ http://en.wikipedia.org/wiki/Library_%28computing%29#Shared_libraries
+__ https://en.wikipedia.org/wiki/Library_%28computing%29#Shared_libraries
 
 
 To build a `static library` with position independent code (required if the main
@@ -207,6 +207,6 @@ __ https://github.com/fmtlib/fmt/blob/master/Android.mk
 Homebrew
 ========
 
-fmt can be installed on OS X using `Homebrew <http://brew.sh/>`_::
+fmt can be installed on OS X using `Homebrew <https://brew.sh/>`_::
 
   brew install fmt