This patch replaces (llvm::|)Optional< with std::optional<.  I'll post
a separate patch to clean up the "using" declarations, #include
"llvm/ADT/Optional.h", etc.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

This patch adds #include <optional> to those files containing
llvm::Optional<...> or Optional<...>.

I'll post a separate patch to actually replace llvm::Optional with
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated.  The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

Return results of URI parsing as 'struct URI' instead of assigning them
via output parameters.

Differential Revision: https://reviews.llvm.org/D112314

Use llvm::Optional<uint16_t> instead of int for port number
in UriParser::Parse(), and use llvm::None to indicate missing port
instead of a magic value of -1.

Differential Revision: https://reviews.llvm.org/D112309

The C headers are deprecated so as requested in D102845, this is replacing them
all with their (not deprecated) C++ equivalent.

Reviewed By: shafik

Differential Revision: https://reviews.llvm.org/D103084

Summary:
When using IPv6 host:port pairs, typically the host is put inside
brackets, such as [2601:1234:...:0213]:5555, and the UriParser
can handle this format.

However, the Android infrastructure in LLDB assumes an additional
brackets around the host:port pair, such that the entire host:port
string can be treated as the host (which is used as an Android Serial
Number), and UriParser cannot handle multiple brackets. Parsing
inputs with such extra backets requires searching the closing bracket
from the right.

Test: BracketedHostnameWithPortIPv6 covers the case mentioned above

Reviewers: #lldb, labath

Reviewed By: labath

Subscribers: kwk, shafik, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D76736

Summary:
A *.cpp file header in LLDB (and in LLDB) should like this:
```
//===-- TestUtilities.cpp -------------------------------------------------===//
```
However in LLDB most of our source files have arbitrary changes to this format and
these changes are spreading through LLDB as folks usually just use the existing
source files as templates for their new files (most notably the unnecessary
editor language indicator `-*- C++ -*-` is spreading and in every review
someone is pointing out that this is wrong, resulting in people pointing out that this
is done in the same way in other files).

This patch removes most of these inconsistencies including the editor language indicators,
all the different missing/additional '-' characters, files that center the file name, missing
trailing `===//` (mostly caused by clang-format breaking the line).

Reviewers: aprantl, espindola, jfb, shafik, JDevlieghere

Reviewed By: JDevlieghere

Subscribers: dexonsmith, wuzish, emaste, sdardis, nemanjai, kbarton, MaskRay, atanasyan, arphaman, jfb, abidh, jsji, JDevlieghere, usaxena95, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D73258