Copy improvements

Smaller improvements around capitalization, tense and style.

data/de.wolfvollprecht.UberWriter.gschema.xml

@@ -8,16 +8,14 @@
       <default>false</default>
       <summary>Dark mode</summary>
       <description>
-        If enabled, the window will be dark themed
-        If disabled, the window will be light themed
-        asked to install them manually.
+        Enable or disable the dark mode.
       </description>
     </key>
     <key name='spellcheck' type='b'>
       <default>true</default>
       <summary>Spellcheck</summary>
       <description>
-        Enable/disable spellchecking in the application.
+        Enable or disable spellchecking.
       </description>
     </key>
     <key name='gradient-overlay' type='b'>
@@ -25,14 +23,14 @@
       <summary>Show gradient overlay</summary>
       <description>
         Show a gradient overlay over the text at the top anf bottom of the window.
-        It can cause performance problems to some users
+        It can cause performance problems to some users.
       </description>
     </key>
     <key name='poll-motion' type='b'>
       <default>true</default>
       <summary>Allow Uberwriter to poll cursor motion</summary>
       <description>
-        Used for hidding the headerbar after 3 seconds if the cursor is not moving.
+        Hide the header and status bars if the cursor is not moving.
       </description>
     </key>
     <key name='open-file-path' type='s'>

data/ui/Preferences.ui

@@ -55,7 +55,7 @@
                 <property name="visible">True</property>
                 <property name="can_focus">False</property>
                 <property name="halign">end</property>
-                <property name="label" translatable="yes">Autospellcheck</property>
+                <property name="label" translatable="yes">Check spelling while typing</property>
                 <property name="justify">right</property>
               </object>
               <packing>

uberwriter/window.py

@@ -129,7 +129,7 @@ class Window(Gtk.ApplicationWindow):
         self.text_editor.set_vadjustment(self.builder.get_object('vadjustment1'))
         self.text_editor.set_wrap_mode(Gtk.WrapMode.WORD_CHAR)
         self.text_editor.connect('focus-out-event', self.focus_out)
-        self.text_editor.get_style_context().connect('changed', self.style_changed)
+        self.text_editor.get_style_context().connect('changed', self.on_style_changed)
 
         self.text_editor.set_top_margin(80)
         self.text_editor.set_bottom_margin(16)
@@ -547,7 +547,7 @@ class Window(Gtk.ApplicationWindow):
             alloc.width = width_request
             self.text_editor.size_allocate(alloc)
 
-    def style_changed(self, _widget, _data=None):
+    def on_style_changed(self, _widget, _data=None):
         pgc = self.text_editor.get_pango_context()
         mets = pgc.get_metrics()
         self.markup_buffer.set_multiplier(
@@ -574,7 +574,7 @@ class Window(Gtk.ApplicationWindow):
         filefilter = Gtk.FileFilter.new()
         filefilter.add_mime_type('text/x-markdown')
         filefilter.add_mime_type('text/plain')
-        filefilter.set_name('MarkDown (.md)')
+        filefilter.set_name('Markdown (.md)')
         filechooser = Gtk.FileChooserDialog(
             _("Save your File"),
             self,