doc: improve awk fconv documenation.

* txr.1: List the no-conversion - operator among the
shortcuts, so it is easier to discover. Add a note that
that fconv is potentially applicable to non-string fields.

1 files changed, 16 insertions, 0 deletions

diff --git a/txr.1 b/txr.1
index 8f9260d4..98612ad7 100644
--- a/txr.1
+++ b/txr.1
@@ -58372,6 +58372,8 @@ Thus fields which are non-numeric strings or the object
 .code nil
 get converted to 0, or 0.0 in the case of
 .codn rz .
+.coIP -
+Performs no conversion: the corresponding field is taken as-is.
 .RE
 .IP
 Because
@@ -58399,6 +58401,20 @@ expression can be used as the condition in an
 clause which triggers the action if one or more fields have been
 extracted, and performs conversions on them.
 
+
+Note: although
+.code fconv
+is intended for converting textual fields, and the semantic descriptions below
+consequently make references to string inputs, the behavior of
+.code fconv
+with respect to non-string fields can be inferred. For instance if a field
+actually holds the floating-point value 3.14, and the
+.code i
+conversion is applied to it, it will produce 3, because it works by
+means of the
+.code toint
+function which.
+
 .TP* Examples:
 
 .verb