Remove duplicate --error-trace from man page (#16133)

Author: kojix2

doc/man/crystal-build.adoc

@@ -44,7 +44,9 @@ require them to stay enabled). `--frame-pointers=always` will always preserve th
 Format of output. Defaults to text. The json format can be used
 to get a more parser-friendly output.
 *--error-trace*::
-Show full error trace.
+Show full error trace. Disabled by default, as the full trace
+usually makes error messages less readable and may not always deliver
+relevant information.
 *--ll*:: 	 Dump LLVM assembly file to output directory.
 *--link-flags* _FLAGS_::
 Pass additional flags to the linker. Though you can specify those
@@ -83,10 +85,6 @@ source code file.
 details.
 *--release*::
 Compile in release mode. Equivalent to *-O3 --single-module*
-*--error-trace*::
-Show full stack trace. Disabled by default, as the full trace
-usually makes error messages less readable and not always deliver
-relevant information.
 *-s*, *--stats*::
 Print statistics about the different compiler stages for the current build. Output time and used memory for each compiler process.
 *-p*, *--progress*::

man/crystal.1

@@ -183,7 +183,9 @@ to get a more parser\-friendly output.
 .sp
 \fB\-\-error\-trace\fP
 .RS 4
-Show full error trace.
+Show full error trace. Disabled by default, as the full trace
+usually makes error messages less readable and may not always deliver
+relevant information.
 .RE
 .sp
 \fB\-\-ll\fP
@@ -259,13 +261,6 @@ details.
 Compile in release mode. Equivalent to \fB\-O3 \-\-single\-module\fP
 .RE
 .sp
-\fB\-\-error\-trace\fP
-.RS 4
-Show full stack trace. Disabled by default, as the full trace
-usually makes error messages less readable and not always deliver
-relevant information.
-.RE
-.sp
 \fB\-s\fP, \fB\-\-stats\fP
 .RS 4
 Print statistics about the different compiler stages for the current build. Output time and used memory for each compiler process.