[docs] mention logfmt in the features page

Author: tstack

docs/03_features.md

@@ -19,9 +19,11 @@ left-hand side help to show which file a message belongs to.
 ## Automatic Log Format Detection
 
 The log message format is automatically determined by lnav while scanning your
-files.   The following formats are built in by default:
+files.  The following are some of the [formats that are built in by default](https://docs.lnav.org/en/latest/formats.html):
 
 * Common Web Access Log format
+* W3C Extended Log File Format
+* logfmt
 * CUPS page_log
 * Syslog
 * Glog
@@ -32,6 +34,10 @@ files.   The following formats are built in by default:
 * Strace
 * sudo
 
+If your log file format is JSON-lines or can be matched by a PCRE regular
+expression, you can define your own format in a
+[JSON file](https://docs.lnav.org/en/latest/formats.html#defining-a-new-format).
+
 GZIP'ed and BZIP2'ed files are also detected automatically and decompressed on-the-fly.
 
 ## Filters

docs/source/formats.rst

@@ -28,7 +28,7 @@ supported:
   self-describing, so **lnav** will read the header to determine the shape of
   the file.
 * The
-  `W3C Extend Log File Format <https://www.w3.org/TR/WD-logfile.html>`_
+  `W3C Extended Log File Format <https://www.w3.org/TR/WD-logfile.html>`_
   is supported in lnav versions v0.10.0+.  The W3C log format is
   self-describing, so **lnav** will read the header to determine the shape of
   the file.