Update usr_51.txt only

Author: h-east

en/usr_51.txt

@@ -103,8 +103,8 @@ NOT LOADING
 
 It is possible that a user doesn't always want to load this plugin.  Or the
 system administrator has dropped it in the system-wide plugin directory, but a
-user has his own plugin he wants to use.  Then the user must have a chance to
-disable loading this specific plugin.  These lines will make it possible: >
+user has their own plugin they want to use.  Then the user must have a chance
+to disable loading this specific plugin.  These lines will make it possible: >
 
   7	if exists("g:loaded_typecorrect")
   8	  finish
@@ -136,7 +136,7 @@ item can be used: >
 
 The "<Plug>TypecorrAdd;" thing will do the work, more about that further on.
 
-The user can set the "g:mapleader" variable to the key sequence that he wants
+The user can set the "g:mapleader" variable to the key sequence that they want
 plugin mappings to start with.  Thus if the user has done: >
 
 	g:mapleader = "_"
@@ -147,16 +147,16 @@ will be used, which is a backslash.  Then a map for "\a" will be defined.
 Note that <unique> is used, this will cause an error message if the mapping
 already happened to exist. |:map-<unique>|
 
-But what if the user wants to define his own key sequence?  We can allow that
-with this mechanism: >
+But what if the user wants to define their own key sequence?  We can allow
+that with this mechanism: >
 
  19	if !hasmapto('<Plug>TypecorrAdd;')
  20	  map <unique> <Leader>a  <Plug>TypecorrAdd;
  21	endif
 
 This checks if a mapping to "<Plug>TypecorrAdd;" already exists, and only
 defines the mapping from "<Leader>a" if it doesn't.  The user then has a
-chance of putting this in his vimrc file: >
+chance of putting this in their vimrc file: >
 
 	map ,c  <Plug>TypecorrAdd;
 
@@ -262,7 +262,7 @@ Now let's add a user command to add a correction: >
 The user command is defined only if no command with the same name already
 exists.  Otherwise we would get an error here.  Overriding the existing user
 command with ":command!" is not a good idea, this would probably make the user
-wonder why the command he defined himself doesn't work.  |:command|
+wonder why the command they defined themselves doesn't work.  |:command|
 If it did happen you can find out who to blame with: >
 
 	verbose command Correct
@@ -494,7 +494,7 @@ An example of how to define functionality in a filetype plugin: >
 |hasmapto()| is used to check if the user has already defined a map to
 <Plug>JavaImport;.  If not, then the filetype plugin defines the default
 mapping.  This starts with |<LocalLeader>|, which allows the user to select
-the key(s) he wants filetype plugin mappings to start with.  The default is a
+the key(s) they want filetype plugin mappings to start with.  The default is a
 backslash.
 "<unique>" is used to give an error message if the mapping already exists or
 overlaps with an existing mapping.