`x` is often criticized as hard to predict due to its slightly complex
behaviour of selecting next line if the current one is fully selected.
Change `x` to use the previous `<a-x>` behaviour, and change `<a-x>` to
trim to fully selected lines as `<a-X>` did.
Adapt existing indentation script to the new behaviour
As it was before, when you had this (| = cursor):
``` json
{
"foo": {|
}
```
and hit <ret>, this would happen:
``` json
{
"foo": {
|
}
```
when it should have been this:
``` json
{
"foo": {
|
}
```
When a closing brace or bracket is typed, it should automatically match
indentation with it's opener. Because of an unescaped ']' literal the regexp
didn't work.
This commit allows using the <semicolon> expansion in commands, instead
of `\;`.
It makes commands look more elegant, and prevents new-comers from
falling into the trap of using <a-;> without escaping the semicolon.
