Update logging calls so they work in sphinx v2.3

Add documentation for the thermal neutron back to back functions

Use cmake generate_mantid_export_header to generate DllConfig.h (Algorithms)

Co-Authored-By: Harrietbrown <49688535+Harrietbrown@users.noreply.github.com>

Replace header guards in tools with pragma once.

Replace header guards in RemoteAlgorithms and RemoteJobManager with pragma once

Replace header guards in TestHelpers and Types with pragma once

Replace header guards in qt/icons and qt/paraview_ext with pragma once

Replace header guards in Testing with pragma once.

Replace header guards in MantidPlot with pragma once

Fix Plot Type being in context menu on plot with only one line

Add documentation for UserFunctionMD

Replace header guards in Geometry with pragma once

This is being done in stages. I've made this change on the Algorithms project
The change consists of removing the manually created DllConfig.h header and replacing
it with one generated during the build by cmake. The MANTID_ALGORITHMS_DLL macro defined
in DllConfig.had was already partially used in the Algorithms project - so some classes
had the attribute DllExport and others already used MANTID_ALGORITHMS_DLL.
I've made it so all classes now use MANTID_ALGORITHMS_DLL.
The DllExport macro was defined in Kernel\System.h so I've removed this include from a
lot of files and replaced it with MantidAlgorithms\DllConfig.h.

As an aside the client projects that use Algorithms such as AlgorithmsTest were working
without this change so it appears that having DllImport present on a class definition
(which is what MANTID_ALGORITHMS_DLL expands to in client executables) is optional

Replace header guards in qt/scientific_interfaces with pragma once

Replace header guards in MD and MPI algorithms with pragma once

This commit removes the unneeded header guards in IMDDimension.cpp

MatrixWorkspace::findY

Replace header guards in LiveData with pragma once

Replace header guards in DataObjects with pragma once

Replace header guards in DataHandling with pragma once

Signed-off-by: Steven Hahn <hahnse@ornl.gov>

Updated Spectoscopy release notes

Signed-off-by: Steven Hahn <hahnse@ornl.gov>

This commit replaces all header guards in MantidPlot with #pragma once.

Fix unhandled exception when you enable filled areas more than once on a waterfall plot

Replace header guards in qt/Widgets with pragma once

Adjust autoscaling behaviour in Muon Analysis

This commit replaces all header guards in tools with #pragma once.

This includes docs for ThermalNeutronBk2BkExpAlpha, ThermalNeutronBk2BkExpBeta, ThermalNeutronBk2BkExpSigma and ThermalNeutronDtoTOFFunction

This commit replaces all header guards in testing with #pragma once.

Fix typo in PyChopGui

Merge pull request #28298 from mantidproject/28200_replace_WorkflowAlgorithms_and_class_maker_header_guards

Replace WorkflowAlgorithms and class maker header guards

Signed-off-by: Steven Hahn <hahnse@ornl.gov>