simplemerge: simplify and rename `render_markers()`
`render_markers()` now always renders minimized 2-way markers, so
let's simplify and rename it accordingly.
Differential Revision: https://phab.mercurial-scm.org/D11979
BasedOnStyle: LLVM
IndentWidth: 8
UseTab: ForIndentation
BreakBeforeBraces: Linux
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
AllowShortBlocksOnASingleLine: false
AllowShortFunctionsOnASingleLine: false
IncludeCategories:
- Regex: '^<'
Priority: 1
- Regex: '^"'
Priority: 2