Just a bit of minor cleanup

Signed-off-by: Tim Smith <tsmith84@gmail.com>

* Fix WASM bullet/code indentation

* Use `console` code highlighting where appropriate

… which handles the prefix `$` correctly.

* Migrate feature proposal template to MarkDown

* Set language on code blocks

I wanted to point out there's --output=all.

`make benchmark ARGS=../benchmark/erb_render.yml` does not work.

```
% make benchmark ARGS=../benchmark/erb_render.yml
/Users/kamipo/.rbenv/shims/ruby --disable=gems -rrubygems -I./benchmark/lib ./benchmark/benchmark-driver/exe/benchmark-driver \
	            --executables="compare-ruby::/Users/kamipo/.rbenv/shims/ruby --disable=gems -I.ext/common --disable-gem" \
	            --executables="built-ruby::./miniruby -I./lib -I. -I.ext/common  ./tool/runruby.rb --extout=.ext  -- --disable-gems --disable-gem" \
	            ../benchmark/erb_render.yml 
Traceback (most recent call last):
	6: from ./benchmark/benchmark-driver/exe/benchmark-driver:112:in `<main>'
	5: from ./benchmark/benchmark-driver/exe/benchmark-driver:112:in `flat_map'
	4: from ./benchmark/benchmark-driver/exe/benchmark-driver:112:in `each'
	3: from ./benchmark/benchmark-driver/exe/benchmark-driver:122:in `block in <main>'
	2: from /Users/kamipo/.rbenv/versions/2.6.6/lib/ruby/2.6.0/psych.rb:577:in `load_file'
	1: from /Users/kamipo/.rbenv/versions/2.6.6/lib/ruby/2.6.0/psych.rb:577:in `open'
/Users/kamipo/.rbenv/versions/2.6.6/lib/ruby/2.6.0/psych.rb:577:in `initialize': No such file or directory @ rb_sysopen - ../benchmark/erb_render.yml (Errno::ENOENT)
make: *** [benchmark] Error 1

% make benchmark ARGS=benchmark/erb_render.yml
/Users/kamipo/.rbenv/shims/ruby --disable=gems -rrubygems -I./benchmark/lib ./benchmark/benchmark-driver/exe/benchmark-driver \
	            --executables="compare-ruby::/Users/kamipo/.rbenv/shims/ruby --disable=gems -I.ext/common --disable-gem" \
	            --executables="built-ruby::./miniruby -I./lib -I. -I.ext/common  ./tool/runruby.rb --extout=.ext  -- --disable-gems --disable-gem" \
	            benchmark/erb_render.yml 
Calculating -------------------------------------
                     compare-ruby  built-ruby 
          erb_render     825.454k    783.664k i/s -      1.500M times in 1.817181s 1.914086s

Comparison:
                       erb_render
        compare-ruby:    825454.4 i/s 
          built-ruby:    783663.8 i/s - 1.05x  slower

```

The vm1_ prefix and vm2_ had had special meaning until
820ad9cb1d72d0897b73dae282df3793814b27e8 and
12068aa4e980ab32a0438408a519030e65dabf5e. AFAIK there's no special
meaning in vm3_ prefix.

As they have confused people (like "In `benchmark` what is difference
between `vm1_`, `vm2_` and `vm3_`"), I'd like to remove the obsoleted
prefix as we obviated that two years ago.

because it's only available for limited platforms for now.
I'll make it portable and show it later.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63954 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

benchmark/README.md: fix help output, which is changed on v0.14.6.
Especially `e1::path1,arg1,...; e2::path2,arg2` part was wrong since `,`
can't be used to split arguments anymore.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63945 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63944 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63942 b2dd03c8-39d4-4d8f-98ff-823fe69b080e