doc: correct wrong use "'s" contractions

src/basic/chase-symlinks.c

@@ -135,7 +135,7 @@ int chase_symlinks_at(
          * Algorithmically this operates on two path buffers: "done" are the components of the path we
          * already processed and resolved symlinks, "." and ".." of. "todo" are the components of the path we
          * still need to process. On each iteration, we move one component from "todo" to "done", processing
-         * it's special meaning each time. We always keep an O_PATH fd to the component we are currently
+         * its special meaning each time. We always keep an O_PATH fd to the component we are currently
          * processing, thus keeping lookup races to a minimum.
          *
          * Suggested usage: whenever you want to canonicalize a path, use this function. Pass the absolute

src/core/job.c

@@ -1001,7 +1001,7 @@ int job_finish_and_invalidate(Job *j, JobResult result, bool recursive, bool alr
         }
 
         /* A special check to make sure we take down anything RequisiteOf= if we aren't active. This is when
-         * the verify-active job merges with a satisfying job type, and then loses it's invalidation effect,
+         * the verify-active job merges with a satisfying job type, and then loses its invalidation effect,
          * as the result there is JOB_DONE for the start job we merged into, while we should be failing the
          * depending job if the said unit isn't in fact active. Oneshots are an example of this, where going
          * directly from activating to inactive is success.

src/core/unit.c

@@ -905,7 +905,7 @@ static int unit_reserve_dependencies(Unit *u, Unit *other) {
         /* Let's reserve some space in the dependency hashmaps so that later on merging the units cannot
          * fail.
          *
-         * First make some room in the per dependency type hashmaps. Using the summed size of both unit's
+         * First make some room in the per dependency type hashmaps. Using the summed size of both units'
          * hashmaps is an estimate that is likely too high since they probably use some of the same
          * types. But it's never too low, and that's all we need. */
 

src/home/homed-manager.c

@@ -1626,7 +1626,7 @@ void manager_revalidate_image(Manager *m, Home *h) {
         assert(h);
 
         /* Frees an automatically discovered image, if it's synthetic and its image disappeared. Unmounts any
-         * image if it's mounted but it's image vanished. */
+         * image if it's mounted but its image vanished. */
 
         if (h->current_operation || !ordered_set_isempty(h->pending_operations))
                 return;

src/shared/bus-unit-util.c

@@ -2757,7 +2757,7 @@ int unit_load_state(sd_bus *bus, const char *name, char **load_state) {
         if (!path)
                 return log_oom();
 
-        /* This function warns on it's own, because otherwise it'd be awkward to pass
+        /* This function warns on its own, because otherwise it'd be awkward to pass
          * the dbus error message around. */
 
         r = sd_bus_get_property_string(