Fix some typos and language issues in the documentation

HACKING.md

@@ -8,7 +8,7 @@ steps you should take.
 
 # Running dunst
 
-For building dunst, you should take a look at the README. After dunst is build,
+For building dunst, you should take a look at the README. After dunst is built,
 you can run it with:
 
         ./dunst

docs/dunst.5.pod

@@ -11,12 +11,12 @@ doesn't change the result.
 
 The 'global' section contains the general settings applying to all of dunst. The
 rest of the settings can be specified via rules and can be located in any
-section. These rules can change a notification based on it's properties. There
-are filtering rules and modifying rules. The filtering rules specify on what
-notifications the rule is applied and the modifying rules specify what is
-changed about the matching notifications. Some special sections have implied
-filters that cannot be changed. The "global" section, for example has no
-filters, thus applies to all notifications.
+section. These rules can change a notification based on its properties. There
+are filtering rules and modifying rules. Filtering rules specify what
+notifications the rule applies to. Modifying rules specify changes
+to the matching notifications. Some special sections have implied
+filters that cannot be changed. For example, the "global" section has no
+filters: it applies to all notifications.
 
 See RULES for more details.
 

src/draw.c

@@ -744,7 +744,7 @@ static void render_content(cairo_t *c, struct colored_layout *cl, int width, dou
                 double half_frame_width = frame_width / 2.0;
 
                 /* Draw progress bar
-                * TODO: Modify draw_rounde_rect to fix blurry lines due to fractional scaling
+                * TODO: Modify draw_rounded_rect to fix blurry lines due to fractional scaling
                 * Note: the bar could be drawn a bit smaller, because the frame is drawn on top 
                 */
                 // left side (fill)