Add some docs for command replacements

doc/help/commands.asciidoc

@@ -4,6 +4,18 @@
 
 = Commands
 
+In qutebrowser, all keybindings are mapped to commands.
+
+Some commands are hidden, which means they don't show up in the command
+completion when pressing `:`, as they're typically not useful to run by hand.
+
+In the commandline, there are also some variables you can use:
+
+- `{url}` expands to the URL of the current page
+- `{url:pretty}` expands to the URL in decoded format
+- `{clipboard}` expands to the clipboard contents
+- `{primary}` expands to the primary selection contents
+
 == Normal commands
 .Quick reference
 [options="header",width="75%",cols="25%,75%"]

qutebrowser/commands/__init__.py

@@ -17,4 +17,15 @@
 # You should have received a copy of the GNU General Public License
 # along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.
 
-"""Utilities and classes regarding to commands."""
+"""In qutebrowser, all keybindings are mapped to commands.
+
+Some commands are hidden, which means they don't show up in the command
+completion when pressing `:`, as they're typically not useful to run by hand.
+
+In the commandline, there are also some variables you can use:
+
+- `{url}` expands to the URL of the current page
+- `{url:pretty}` expands to the URL in decoded format
+- `{clipboard}` expands to the clipboard contents
+- `{primary}` expands to the primary selection contents
+"""

scripts/dev/src2asciidoc.py

@@ -37,7 +37,7 @@ sys.path.insert(0, os.path.join(os.path.dirname(__file__), os.pardir,
 # We import qutebrowser.app so all @cmdutils-register decorators are run.
 import qutebrowser.app
 from scripts import asciidoc2html, utils
-from qutebrowser import qutebrowser
+from qutebrowser import qutebrowser, commands
 from qutebrowser.commands import cmdutils, argparser
 from qutebrowser.config import configdata
 from qutebrowser.utils import docutils, usertypes
@@ -320,7 +320,8 @@ def generate_commands(filename):
     """Generate the complete commands section."""
     with _open_file(filename) as f:
         f.write(FILE_HEADER)
-        f.write("= Commands\n")
+        f.write("= Commands\n\n")
+        f.write(commands.__doc__)
         normal_cmds = []
         hidden_cmds = []
         debug_cmds = []