ui: add new config option for help text width
Before this patch, when printing help text using `hg help`, or `hg log -h`,
the output will wrap at 78 chars even if the user has a bigger terminal width
and there is no config option to change it, making the experience different
from the commonly used `man` tool.
This patch introduces a new config option `ui.textwidth`, which replaces the
hardcoded number. It's set to 78 by default to maintain compatibility. When
set to 0, `hg help` will behave more like `man`.
$ hg init
$ mkdir alpha
$ touch alpha/one
$ mkdir beta
$ touch beta/two
$ hg add alpha/one beta/two
$ hg ci -m "start"
$ echo 1 > alpha/one
$ echo 2 > beta/two
everything
$ hg diff --nodates
diff -r 7d5ef1aea329 alpha/one
--- a/alpha/one
+++ b/alpha/one
@@ -0,0 +1,1 @@
+1
diff -r 7d5ef1aea329 beta/two
--- a/beta/two
+++ b/beta/two
@@ -0,0 +1,1 @@
+2
beta only
$ hg diff --nodates beta
diff -r 7d5ef1aea329 beta/two
--- a/beta/two
+++ b/beta/two
@@ -0,0 +1,1 @@
+2
inside beta
$ cd beta
$ hg diff --nodates .
diff -r 7d5ef1aea329 beta/two
--- a/beta/two
+++ b/beta/two
@@ -0,0 +1,1 @@
+2
relative to beta
$ cd ..
$ hg diff --nodates --root beta
diff -r 7d5ef1aea329 two
--- a/two
+++ b/two
@@ -0,0 +1,1 @@
+2
inside beta
$ cd beta
$ hg diff --nodates --root .
diff -r 7d5ef1aea329 two
--- a/two
+++ b/two
@@ -0,0 +1,1 @@
+2
$ cd ..