tools: fix typos

[NathanBaulch]

Just thought I'd contribute some typo fixes that I stumbled on. Nothing controversial (hopefully).

Use the following command to get a quick summary of the specific corrections made:

git diff HEAD^! --word-diff-regex='\w+' -U0 \
  | grep -E '\[\-.*\-\]\{\+.*\+\}' \
  | sed -r 's/.*\[\-(.*)\-\]\{\+(.*)\+\}.*/\1 \2/' \
  | sort | uniq -c | sort -n

FWIW, the top typos are:

• exected
• middelware
• suppresions
• taget
• paraghraph
• overlayed
• configuation
• collapsable
• curren
• eror
• fiter
• reponsible
• seperator
• varible
• vertial