[PATCH] change_table cleanup

This patch cleans up the changes that were introduced with #71 [patch] change_table block. http://github.com/rails/rails/co...

It affects three areas:

1. code
2. documentation
3. whitespace

1. Code

The documentation said reference/remove_reference could be used (in addition to their plural names) but these methods were missing. Added proper aliases and tests.

2. Documentation

Tried to make things more consistent.

Fixes:

• Added previously mentioned reference/remove_reference to list of available transformations
• Pluralized/Singularized Examples depending on number listed
• Made example descriptions into small headers
• Removed dangling See that was never completed
• Changed See to SchemaStatements#add_timestamps as #timestamps doesn't exist
• Removed single t.removes() example from doc as there is only a singular method makes sense

3. Whitespace

• Changed sentence spacing from two spaces to one, since it gets collapsed anyways
• Empty lines and dangling spaces removed in entire schema_definitions.rb file

I tried to make things more consistent and will appreciate feedback:

• I added reference alias to be consistent with docs, but are all three aliases needed? (reference , references , belong_to) As a sentence, foo references/belongs_to bar sounds proper as "noun verb noun"
• In contrast, t.removes zig should just be singular to be consistent with the other methods
• Does the whitespace cleanup in the entire file dilute the focus of main fixes and should it be left to a separate patch?

Patch is attached or available in my fork at: git://github.com/thetamind/rails.git (change_table_doc_fix or master branch)