feat: Support .hledger extensions out of the box

c.f. https://gitlab.com/nobodyinperson/hledger-utils/-/issues/26

Author: alerque

ftdetect/ledger.vim

@@ -1,2 +1,8 @@
 " vint: -ProhibitAutocmdWithNoGroup
-autocmd BufNewFile,BufRead *.ldg,*.ledger,*.journal setfiletype ledger
+
+" Semi-canonical or common file extensions
+autocmd BufNewFile,BufRead *.journal,*.ledger,*.hledger setfiletype ledger
+
+" Deprecated or suspiciusly low usage extensions
+" TODO: Consider hiding these behind an off-by-default config flag
+autocmd BufNewFile,BufRead *.ldg,*.j, setfiletype ledger