discovery: prevent deleting items from a dictionary
Removing elements from Python dictionary is expensive. So let's prevent adding
them instead.
I added a newline to make code look a bit better.
Differential Revision: https://phab.mercurial-scm.org/D6146
BasedOnStyle: LLVM
IndentWidth: 8
UseTab: ForIndentation
BreakBeforeBraces: Linux
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
AllowShortBlocksOnASingleLine: false
AllowShortFunctionsOnASingleLine: false
IncludeCategories:
- Regex: '^<'
Priority: 1
- Regex: '^"'
Priority: 2