Add or update a style definition for TFL_spec

Usage

# S3 method for class 'TFL_spec'
add_style(spec, id, ...)

spec

TFL_spec object

id

Style identifier (auto-generated if NULL)

...

Style modifiers created with s_* functions

Allowed modifiers: s_font(), s_paragraph(), s_table_style().
s_paragraph() may itself contain nested modifiers s_spacing() and s_indents().
Modifiers are merged into the named style using a last-win strategy.

Updated spec object