front-end: fix documentation regarding theme.less file

The documentation stated that a theme.less file can be placed in the
Kallithea root directory, but this is not true. The file is expected in
kallithea/front-end to take effect.

Update the documentation and .hgignore file.

.hgignore

@@ -24,6 +24,7 b' syntax: regexp'
 ^\.coverage$
 ^kallithea/front-end/node_modules$
 ^kallithea/front-end/package-lock\.json$
+^kallithea/front-end/theme\.less$
 ^kallithea/front-end/tmp$
 ^kallithea/public/codemirror$
 ^kallithea/public/css/select2-spinner\.gif$
@@ -41,7 +42,6 b' syntax: regexp'
 ^kallithea/public/js/jquery\.flot\.time\.js$
 ^kallithea/public/js/jquery\.min\.js$
 ^kallithea/public/js/select2\.js$
-^theme\.less$
 ^kallithea\.db$
 ^test\.db$
 ^Kallithea\.egg-info$

docs/usage/customization.rst

@@ -23,10 +23,11 b' Style sheet customization with Less'
 
 Kallithea uses `Bootstrap 3`_ and Less_ for its style definitions. If you want
 to make some customizations, we recommend to do so by creating a ``theme.less``
-file. When you create a file named ``theme.less`` in the Kallithea root
-directory, you can use this file to override the default style. For example,
-you can use this to override ``@kallithea-theme-main-color``,
-``@kallithea-logo-url`` or other `Bootstrap variables`_.
+file. When you create a file named ``theme.less`` in directory
+``kallithea/front-end/`` inside the Kallithea installation, you can use this
+file to override the default style. For example, you can use this to override
+``@kallithea-theme-main-color``, ``@kallithea-logo-url`` or other `Bootstrap
+variables`_.
 
 After creating the ``theme.less`` file, you need to regenerate the CSS files, by
 running::