Miscellaneous documentation additions.

Added notes explaining how [expr, ..expr] form is used, targeted at
individuals like me who thought it was more general and handled
dynamic repeat expressions.  (I left a TODO for this section in a
comment, but perhaps that is bad form for the manual...)

Added example of `do` syntax with a function of arity > 1; yes, one
should be able to derive this from the text above it, but it is still
a useful detail to compare and contrast against the arity == 1 case.

Added example of using for expression over a uint range, since someone
who is most used to write `for(int i; i < lim; i++) { ... }` will
likely want to know how to translate that form (regardless of whether
it happens to be good style or not for their use-case).

Added note about the semi-strange meaning of "fixed size" of vectors
in the vector type section.
Fixes mozilla/rust#3612.
Spelling fixes; replaced `size` with `capacity` in few places.
Cleanup wording around the awkward "and so on is . ." in the README.txt.
Updated to reflect alpha-rename of constant/static items section.
Moved float str buffer constants to the strconv module
pre-rebase commit
Switched over a bunch of splitting funktions to non-allocating iterators
Isolated bug, static vector seems to behave differently than fixed sized one
Fixed all use sites and tests
Added missing lifetime annotations, doc and whitespace cleanups
auto merge of #5553 : pnkfelix/rust/doc-fixes-for-0.6-incoming, r=sanxiyn
rustdoc: Sanitize links harder
rustdoc: Build the crate config correctly. Fixes #5011
rustdoc: Handle impl method visibility correctly. #5533
rustdoc: Add type bounds to impls
rustdoc: Tweak list style
auto merge of #5549 : brson/rust/rustdoc, r=brson

r?
Added more missing lifetime annotations
Fix #4855: handle bot in regionck