Docs: Improve the documentation for kittens

Add more text roles and links.
Add an example that broadcasts only to other windows in the current tab.
Initial capitalization of the key names in the kbd text role.
Add Python type hints for custom kittens.
Note about hyperlink support for ls on macOS.
Add description text for show_key.

docs/marks.rst

@@ -9,12 +9,12 @@ running programs or similar. Lets start with a few examples:
 Examples
 ----------
 
-Suppose we want to be able to highlight the word ERROR in the current window.
-Add the following to :file:`kitty.conf`::
+Suppose we want to be able to highlight the word :code:`ERROR` in the current
+window. Add the following to :file:`kitty.conf`::
 
     map f1 toggle_marker text 1 ERROR
 
-Now when you press :kbd:`F1` all instances of the word :code:`ERROR` will be
+Now when you press :kbd:`F1`, all instances of the word :code:`ERROR` will be
 highlighted. To turn off the highlighting, press :kbd:`F1` again.
 If you want to make it case-insensitive, use::
 
@@ -39,25 +39,24 @@ can control the colors used for these groups in :file:`kitty.conf` with::
 
 
 .. note::
-    For performance reasons, matching is done per line only, and only when that line is
-    altered in any way. So you cannot match text that stretches across multiple
-    lines.
+    For performance reasons, matching is done per line only, and only when that
+    line is altered in any way. So you cannot match text that stretches across
+    multiple lines.
 
 
 Creating markers dynamically
 ---------------------------------
 
 If you want to create markers dynamically rather than pre-defining them in
-:file:`kitty.conf` you can do so as follows::
+:file:`kitty.conf`, you can do so as follows::
 
     map f1 create_marker
     map f2 remove_marker
 
 Then pressing :kbd:`F1` will allow you to enter the marker definition and set
 it and pressing :kbd:`F2` will remove the marker. ``create_marker`` accepts
-the same syntax as ``toggle_marker`` above. Note that while creating
-markers, the prompt has history so you can easily re-use previous marker
-expressions.
+the same syntax as ``toggle_marker`` above. Note that while creating markers,
+the prompt has history so you can easily re-use previous marker expressions.
 
 You can also use the facilities for :doc:`remote-control` to dynamically
 add/remove markers.
@@ -66,14 +65,15 @@ add/remove markers.
 Scrolling to marks
 --------------------
 
-kitty has an action to scroll to the next line that contains a mark. You can
-use it by mapping it to some shortcut in :file:`kitty.conf`::
+kitty has an action :ac:`scroll_to_mark` to scroll to the next line that
+contains a mark. You can use it by mapping it to some shortcut in
+:file:`kitty.conf`::
 
     map ctrl+p scroll_to_mark prev
     map ctrl+n scroll_to_mark next
 
-Then pressing :kbd:`ctrl+p` will scroll to the first line in the scrollback
-buffer above the current top line that contains a mark. Pressing :kbd:`ctrl+n`
+Then pressing :kbd:`Ctrl+P` will scroll to the first line in the scrollback
+buffer above the current top line that contains a mark. Pressing :kbd:`Ctrl+N`
 will scroll to show the first line below the current last line that contains
 a mark. If you wish to jump to a mark of a specific type, you can add that to
 the mapping::
@@ -86,7 +86,7 @@ Which will scroll only to marks of type 1.
 The full syntax for creating marks
 -------------------------------------
 
-The syntax of the :code:`toggle_marker` command is::
+The syntax of the :ac:`toggle_marker` action is::
 
     toggle_marker <marker-type> <specification>
 
@@ -94,16 +94,16 @@ Here :code:`marker-type` is one of:
 
 * :code:`text` - simple substring matching
 * :code:`itext` - case-insensitive substring matching
-* :code:`regex` - A python regular expression
-* :code:`iregex` - A case-insensitive python regular expression
-* :code:`function` - An arbitrary function defined in a python file, see :ref:`marker_funcs`.
+* :code:`regex` - A Python regular expression
+* :code:`iregex` - A case-insensitive Python regular expression
+* :code:`function` - An arbitrary function defined in a Python file, see :ref:`marker_funcs`.
 
 .. _marker_funcs:
 
 Arbitrary marker functions
 -----------------------------
 
-You can create your own marker functions. Create a python file named
+You can create your own marker functions. Create a Python file named
 :file:`mymarker.py` and in it create a :code:`marker` function. This
 function receives the text of the line as input and must yield three numbers,
 the starting character position, the ending character position and the mark
@@ -122,6 +122,7 @@ Save this file somewhere and in :file:`kitty.conf`, use::
 
     map f1 toggle_marker function /path/to/mymarker.py
 
-If you save the file in the kitty config directory, you can use::
+If you save the file in the :ref:`kitty config directory <confloc>`, you can
+use::
 
     map f1 toggle_marker function mymarker.py