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Found via `codespell -q 3 -I ../mantid-word-whitelist.txt` where whitelist consists of:  
```
alloced
allws
ang
ans
arithmetics
dum
dur
iff
isnt
ith
lod
mut
nd
originaly
sav
splitted
te
tim
uint
```

# Please enter a commit message to explain why this merge is necessary,
# especially if it merges an updated upstream into a topic branch.
#
# Lines starting with '#' will be ignored, and an empty message aborts
# the commit.

Merge done to enable documentation be be fixed, because of removal of
alias directive and addition of related algorithms directive.
Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>

Upper case causes it not to work

re #22143

To avoid clashing with the default seealso directive
re #22143

re #21243

re #11821

Uses # to denote a html h3 heading.
Refs #9562

The converted text is stored in separate .rst files in the docs directory.
Refs #9562