Add --changed-after alias.

And make some small tweaks to the help text and man page.

Closes: #982

doc/fd.1

@@ -286,12 +286,16 @@ Files with modification times greater than the argument will be returned.
 The argument can be provided as a duration (\fI10h, 1d, 35min\fR) or as a specific point
 in time in either full RFC3339 format with time zone, or as a date or datetime in the
 local time zone (\fIYYYY-MM-DD\fR or \fIYYYY-MM-DD HH:MM:SS\fR).
-.B --change-newer-than
-can be used as an alias.
+\fB\-\-change-newer-than\fR,
+.B --newer
+or
+.B --changed-after
+can be used as aliases.
 
 Examples:
   \-\-changed-within 2weeks
   \-\-change-newer-than "2018-10-27 10:00:00"
+  \-\-newer 2018-10-27
 .TP
 .BI "\-\-changed-before " date|duration
 Filter results based on the file modification time.
@@ -300,7 +304,9 @@ The argument can be provided as a duration (\fI10h, 1d, 35min\fR) or as a specif
 in time in either full RFC3339 format with time zone, or as a date or datetime in the
 local time zone (\fIYYYY-MM-DD\fR or \fIYYYY-MM-DD HH:MM:SS\fR).
 .B --change-older-than
-can be used as an alias.
+or
+.B --older
+can be used as aliases.
 
 Examples:
   \-\-changed-before "2018-10-27 10:00:00"

src/cli.rs

@@ -335,8 +335,11 @@ pub struct Opts {
         long,
         alias("change-newer-than"),
         alias("newer"),
+        alias("changed-after"),
         value_name = "date|dur",
-        long_help = "Filter results based on the file modification time. The argument can be provided \
+        long_help = "Filter results based on the file modification time. \
+                     Files with modification times greater than the argument are returned. \
+                     The argument can be provided \
                      as a specific point in time (YYYY-MM-DD HH:MM:SS) or as a duration (10h, 1d, 35min). \
                      If the time is not specified, it defaults to 00:00:00. \
                      '--change-newer-than' or '--newer' can be used as aliases.\n\
@@ -353,7 +356,9 @@ pub struct Opts {
         alias("change-older-than"),
         alias("older"),
         value_name = "date|dur",
-        long_help = "Filter results based on the file modification time. The argument can be provided \
+        long_help = "Filter results based on the file modification time. \
+                     Files with modification times less than the argument are returned. \
+                     The argument can be provided \
                      as a specific point in time (YYYY-MM-DD HH:MM:SS) or as a duration (10h, 1d, 35min). \
                      '--change-older-than' or '--older' can be used as aliases.\n\
                      Examples:\n    \