Implement a `forall` method on the Sequence class that takes a predicate function and returns true only if every element in the sequence satisfies the predicate. The method iterates through all elements, returning false immediately upon encountering any element where the predicate does not return exactly true. Includes core library documentation and a test file verifying behavior with numeric comparisons and non-boolean predicate returns.
Rename indexOf.wren and startsWith.wren test files to index_of.wren and
starts_with.wren respectively, fix missing trailing newlines, update
string class documentation to clarify UTF-8 storage and move the
note about incorrect UTF-8 handling in the index operator, and
remove unnecessary parentheses in string_indexOf native return.
Replace the empty `core-libraries.markdown` placeholder with a comprehensive `core-library.markdown` documenting Object, Class, Bool, and Fiber classes. Update site template to link to the new page. Tweak SCSS styles: reduce body font to 16px/25px, darken header background with text-shadow, adjust code font size and borders, add left margin to main content paragraphs and pre blocks, and refine link colors. Fix prose in functions.markdown to use "arguments" instead of "parameters" and clarify dynamic dispatch wording.
