Fix docs for example/example_group alias methods.

We were getting YARD doc warnings:

$ bin/yard server --reload

[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 122
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 122
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 122
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 125
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 125
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 125
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 134
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 134
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 134
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 138
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 138
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 138
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 141
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 141
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 141
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 144
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 144
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 144
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 147
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 147
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 147
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 150
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 150
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 150
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 153
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 153
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 153
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 156
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 156
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 156
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 159
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 159
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 159
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 162
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 162
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 162
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 231
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 231
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 236
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 236
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 241
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 241
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 245
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 245
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 249
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 249
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 253
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 253
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 257
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 257
Address remaining yard warnings.

[warn]: @param tag has unknown parameter name: notification
    in file `lib/rspec/core/formatters/base_formatter.rb' near line 50
[warn]: @param tag has unknown parameter name: profile
    in file `lib/rspec/core/formatters/profile_formatter.rb' near line 26
[warn]: @param tag has unknown parameter name: notification
    in file `lib/rspec/core/formatters/base_text_formatter.rb' near line 23
[warn]: @param tag has unknown parameter name: notification
    in file `lib/rspec/core/formatters/base_text_formatter.rb' near line 33
[warn]: @param tag has unknown parameter name: summary
    in file `lib/rspec/core/formatters/base_text_formatter.rb' near line 46
[warn]: @param tag has unknown parameter name: notification
    in file `lib/rspec/core/formatters/base_text_formatter.rb' near line 68
Merge pull request #1752 from rspec/address-yard-warnings

Address yard warnings