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.
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# 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>

refs #17274

refs #17241

refs #16005

In addition many (although not all) sphinx warnings corrected

re #16301

refs #16194

re #15544

refs #15906

refs #15765

refs #15765

refs #15767