Candidate for C++20 deserialization features (#2276)

* tag_invoke based custom types (#2219)

* tag_invoke based custom types

Now you can use tag_invoke to add a custom type or a group of custom types.

* Fixing macro usage + Fixing noexcept

* Fixing the usage of #include

We don't need <concepts> at all seems like it

* Fixing tag_invoke impl for MSVC

* Making `tag_invoke` to support `ondemand::document` as well + docs (#2228)

* Making `tag_invoke` to support `ondemand::document` as well + docs

* Fix typos and doc update by @lemire

Co-authored-by: Daniel Lemire <daniel@lemire.me>

* Better docs by @lemire

Co-authored-by: Daniel Lemire <daniel@lemire.me>

* Preserving the old, disallowing in the new

I'm disabling `document::get() &&` if the user has provided a `tag_invoke`d version; otherwise, we retain the compatibility.

---------

Co-authored-by: Daniel Lemire <daniel@lemire.me>

* fix: correct small issues with deserialize (#2232)

* Extending the deserialization code with more defaults + docs (#2233)

* Make custom types easier with some predefined cases + docs

* missing include

* adding Ubuntu 24 CXX 20

* using concepts all the way

* minor tweak

* tiny tweak

* tweaks

* more tweaking

* saving

---------

Co-authored-by: Daniel Lemire <dlemire@lemire.me>

* Making `tag_invoke` a "put" as opposed to a "get" (#2256)

* fix: add tests related to issue 2227 (#2229)

* fix: add tests related to issue 2227

* avoiding name clash

* pedantic fix

* deprecate rvalue get on document

* selectively deprecating

* Fix ndjson spec link (#2234)

* fix ndjson spec link

The link in the readme of parse_many links to a casino spam site

* fix link

* [no-ci] Update README.md

* Make simdjson compile again

* Enable SIMDJSON_SINGLEHEADER=OFF in VS Code

With singleheader on, clangd can't find the right
include files.

* Add missing include directives to static build targets of simdjson. (#2240)

* adding a warning

* adding warning regarding SIMDJSON_BUILD_STATIC_LIB

* release candidate

* pedantic viable size

* Making tag_invoke a feeder instead of a producer

* adding missing undef silencer (#2253)

* Ignore pragma once when amalgamating source files (#2248)

With gcc it causes an error in `simdjson.cpp`:
```
simdjson.cpp:548:9: warning: #pragma once in main file
  548 | #pragma once
      |         ^~~~
```

It had previously been commented out in:
https://github.com/simdjson/simdjson/commit/6ef555e6fb79363fae057a9a46b52cd208d9e305

However, this was lost in an upgrade:
https://github.com/simdjson/simdjson/commit/2a4ff7346813b120f2b5b40e95d69352b593cc9c

* Update CI (#2254)

* adding missing undef silencer

* Updating CI

* more fixes

* fix

* big endian fix

* Moving to the new tag_invoke signature

* Fix nlohmann ambiguity on C++23-enabled clang

* Revert "Merge branch 'master' of https://github.com/simdjson/simdjson into builder_development_branch_extra"

This reverts commit 3eeecbab34, reversing
changes made to 6858b208b4.

---------

Co-authored-by: Daniel Lemire <daniel@lemire.me>
Co-authored-by: Sasha Lopoukhine <superlopuh@gmail.com>
Co-authored-by: John Keiser <john@johnkeiser.com>
Co-authored-by: Tan Li Boon <undisputed-seraphim@users.noreply.github.com>
Co-authored-by: tobil4sk <tobil4sk@outlook.com>

* update CI on the builder_development_branch (no code change) (#2262)

* typo

* General madness simpler, no simpler!!! (#2267)

* Minimal tag_invokes for STL types

* simpler madness

* adding a comment

* missing file

* minor tweaks to style

* fixing incorrect max/min usage

* updating single

* simplify

* validating the idea

* putting back the concept

* moving the include

* guarding

* Cheap General Madness (#2268)

* Some General Concepts and their deserializations

* Resolving ambiguity

* Add missing #include

* C++20 custom deserializer: better documentation (#2269)

* mostly a documentation update.

* missing cpp

* [no-ci] fix comment

* various minor fixes

---------

Co-authored-by: Daniel Lemire <dlemire@lemire.me>

---------

Co-authored-by: M. Bahoosh <12122474+the-moisrex@users.noreply.github.com>
Co-authored-by: Daniel Lemire <dlemire@lemire.me>
Co-authored-by: M. Bahoosh <moisrex@gmail.com>

* minor update

* More documentation regarding builder (#2270)

* minor update

* more improvment to our documentation (builder branch)

* putting back missing functions

* merge candidate

---------

Co-authored-by: M. Bahoosh <moisrex@gmail.com>
Co-authored-by: Daniel Lemire <dlemire@lemire.me>
Co-authored-by: Sasha Lopoukhine <superlopuh@gmail.com>
Co-authored-by: John Keiser <john@johnkeiser.com>
Co-authored-by: Tan Li Boon <undisputed-seraphim@users.noreply.github.com>
Co-authored-by: tobil4sk <tobil4sk@outlook.com>
Co-authored-by: M. Bahoosh <12122474+the-moisrex@users.noreply.github.com>

.github/workflows/ubuntu24-cxx20.yml

@@ -0,0 +1,22 @@
+name: Ubuntu 24.04 CI (CXX 20)
+
+on: [push, pull_request]
+jobs:
+  ubuntu-build:
+    if: >-
+      ! contains(toJSON(github.event.commits.*.message), '[skip ci]') &&
+      ! contains(toJSON(github.event.commits.*.message), '[skip github]')
+    runs-on: ubuntu-24.04
+    strategy:
+      matrix:
+        cxx: [g++-13, clang++-16]
+    steps:
+      - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29 # v4.1.6
+      - name: Prepare
+        run: cmake -DSIMDJSON_CXX_STANDARD=20 -DSIMDJSON_DEVELOPER_MODE=ON  -B build
+        env:
+          CXX: ${{matrix.cxx}}
+      - name: Build
+        run: cmake --build build -j=2
+      - name: Test
+        run: ctest --output-on-failure --test-dir build

.github/workflows/vs17-clang-ci-cxx20.yml

@@ -0,0 +1,37 @@
+name: VS17-CLANG-CI
+
+on: [push, pull_request]
+
+jobs:
+  ci:
+    if: >-
+      ! contains(toJSON(github.event.commits.*.message), '[skip ci]') &&
+      ! contains(toJSON(github.event.commits.*.message), '[skip github]')
+    name: windows-vs17
+    runs-on: windows-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - {gen: Visual Studio 17 2022, arch: x64, build_type: Debug}
+          - {gen: Visual Studio 17 2022, arch: x64, build_type: Release}
+          - {gen: Visual Studio 17 2022, arch: x64, build_type: RelWithDebInfo}
+    steps:
+    - name: checkout
+      uses: actions/checkout@v4
+    - name: Configure
+      run: |
+        cmake -G "${{matrix.gen}}" -A ${{matrix.arch}}  -T ClangCL -DSIMDJSON_DEVELOPER_MODE=ON -DSIMDJSON_COMPETITION=OFF -B build
+    - name: Build
+      run: cmake --build build --config ${{matrix.build_type}} --verbose
+    - name: Run tests
+      run: |
+        cd build
+        ctest -C ${{matrix.build_type}}  -LE explicitonly  --output-on-failure
+    - name: Install
+      run: |
+        cmake --install build --config ${{matrix.build_type}}
+    - name: Test Installation
+      run: |
+        cmake -G "${{matrix.gen}}" -A ${{matrix.arch}}  -B build_install_test tests/installation_tests/find
+        cmake --build build_install_test --config ${{matrix.build_type}}