debuginfo: Make GDB tests use line breakpoints like done in LLDB tests.

On some Windows versions of GDB this is more stable than setting breakpoints via function names.
debuginfo: Enable some GDB tests on Windows.
DOC: improves the str type explanation

Closes #18449
Constants used in range patterns should not be considered unused
Prefer where clauses to impls in trait resolution (not vice versa).

Fixes #18453.
small fix to output of code sample in intro.md
Teach variance checker about the lifetime bounds that appear in trait object types.
Resolve methods called as functions and...

...defined in another crate.

Fixes #18061
Remove FnStyle from DefFn and DefStaticMethod
Cross crait inherant impls
test
Rebasing and review changes
Fix RustDoc bug
rustdoc: stop trying to use font-variants we don't have

Browser-generated weights or slants is the last thing we want...
Update one corrupt webfont

As with last time (where I marked .woff files as binary so that git does
not perform newline normalization), it's unclear how it got corrupted in
the first place.
doc: enable OpenType kerning and ligatures
auto merge of #18177 : nick29581/rust/ufcs2, r=nikomatsakis

r?

closes #18061
auto merge of #18371 : nikomatsakis/rust/issue-18262, r=pcwalton

Teach variance checker about the lifetime bounds that appear in trait object types.

[breaking-change] This patch fixes a hole in the type system which resulted in lifetime parameters that were only used in trait objects not being checked. It's hard to characterize precisely the changes that might be needed to fix target code.

cc #18262 (this fixes the test case by @jakub- but I am not sure if this is the same issue that @alexcrichton was reporting)

r? @pnkfelix 

Fixes #18205
First stage of enum namespacing changes
auto merge of #18422 : michaelwoerister/rust/windows-freeze-fix, r=alexcrichton

On some Windows versions of GDB this is more stable than setting breakpoints via function names. This is also something I wanted to do for some time now because it makes the tests more consistent.

@brson:
These changes are in response to issue #17540. It works on my machine with the toolchain mentioned in the issue. In order to find out if the problem is really worked around, we also need to make the build bots use the newer GDB version again.