Fix typos.

Author: rouilj

doc/user_guide.txt

@@ -60,7 +60,7 @@ are not "resolved".
 If an issue is closed, and a new message is received then it'll be
 reopened to the state of "chatting".
 
-The full set of **prority** and **status** values are:
+The full set of **priority** and **status** values are:
 
 =========== =====================================
 Priority    Description
@@ -329,10 +329,10 @@ arguments:
 ============ =============================================================
 Argument     Description
 ============ =============================================================
-@sort        sort by prop name, optionally preceeded with '-' to give
+@sort        sort by prop name, optionally preceded with '-' to give
              descending or nothing for ascending sorting. The sort
              argument can have several props separated with comma.
-@group       group by prop name, optionally preceeded with '-' or to sort
+@group       group by prop name, optionally preceded with '-' or to sort
              in descending or nothing for ascending order. The group
              argument can have several props separated with comma.
 @columns     selects the columns that should be displayed. Default is
@@ -402,14 +402,14 @@ Subject-line information
 
 The subject line of the incoming message is examined to find one of:
 
-1. a case insentive ``help``,
+1. a case insensitive ``help``,
 2. a match for ``-- key <OneTimeKey>``,
 3. the item that the message is responding to,
 4. the type of item the message should create, or
 5. we default the item class and try some trickiness.
 
 If the subject is ``help`` (case insensitive), the gateway responds
-with an explaination of the interface.
+with an explanation of the interface.
 
 If a one-time key is found, we're processing an in-progress
 registration confirmation.
@@ -766,7 +766,7 @@ the command-line.
 
 When you initialise a new tracker instance you are prompted for the
 admin password. If you want to initialise a tracker non-interactively
-you can put the initialise command and password on the commnd
+you can put the initialise command and password on the command
 line. But this allows others on the host to see the password (using
 the ps command). To initialise a tracker non-interactively without
 exposing the password, create a file (e.g init_tracker) set to mode