docs: correct vi documentation for FGREP command

update documentation to reflect real functionality
-u option doesn't exists and -i option is new

bld/vi/doc/cmd.hlp

@@ -183,14 +183,14 @@ the rest is optional.
 	    syntax as the "map" command. See keyadd for a delayed addition of
 	    keystrokes.
 
-	[fgr]ep (-c) (-u) "string" (file)
+	[fgr]ep (-c) (-i) "string" (file)
 	  - searches for string in the specified wild card (file). (if
-	    (file) is not specified, it defaults to *.c).  Search is
-	    case insensitive, unless -c is specified, in which case
-	    the search is case sensitve.  -u uses the CaseIgnore setting
-	    to determine whether or not to be case sensitive in the search
-	    When all matches are found, a selection window is presented 
-	    with the files that contained string.  
+	    (file) is not specified, it defaults to *.c).  If -c is specified
+	    then the search is case sensitive or if -i is specified then the
+	    search is case insensitive otherwise the CaseIgnore setting is
+	    used to determine whether or not to be case sensitive in the
+	    search.  When all matches are found, a selection window is
+	    presented with the files that contained string.  
 
 	[f]iles
 	  - open a window with a list of all files currently being edited;

docs/doc/vi/cmds.gml

@@ -822,17 +822,17 @@ Replaces all tabs in the current edit buffer with spaces.
 .endfunc
 
 .begfunc FGREP
-.syntx * FGRep '"-c"' '"-u"' &lt.string&gt. &lt.files&gt.
+.syntx * FGRep '"-c"' '"-i"' &lt.string&gt. &lt.files&gt.
 .begdescr
 Searches the file list &parm4 for the string &parm3
 .period
 .np
-The search is by default case insensitive, unless
+If
 .param -c
-is specified, which forces the search to be case sensitive.
-Specifying
-.param -u
-causes the setting of
+is specified then the search to be case sensitive or if
+.param -i
+is specified then the search to be case insensitive otherwise
+the setting of
 .keyref caseignore 1
 to determine whether or not to be case sensitive in the search.
 .np