fix: note title ending removed when it matches parts of extension (#119)

* fix: note title ending removed when it matches parts of extension

By using [] we provide a character set rather than a direct match with ().
Lua patterns don't allow N-captures with (), so we continue executing
the pattern until there are no more substitutions being executed.

fixes #118

* fix: refactor extension stripping from title

Don't worry about n-capture, once is enough.
Turned it into a fn so it can be used elsewhere.

refs #118

lua/telekasten.lua

@@ -341,6 +341,12 @@ local function save_all_tk_buffers()
     end
 end
 
+-- strip an extension from a file name, escaping "." properly, eg:
+-- strip_extension("path/Filename.md", ".md") -> "path/Filename"
+local function strip_extension(str, ext)
+    return str:gsub("(" .. ext:gsub("%.", "%%.") .. ")$", "")
+end
+
 -- ----------------------------------------------------------------------------
 -- image stuff
 -- ----------------------------------------------------------------------------
@@ -2009,7 +2015,7 @@ local function CreateNoteSelectTemplate(opts)
     -- vim.ui.input causes ppl problems - see issue #4
     -- vim.ui.input({ prompt = "Title: " }, on_create_with_template)
     local title = vim.fn.input("Title: ")
-    title = title:gsub("[" .. M.Cfg.extension .. "]+$", "")
+    title = strip_extension(title, M.Cfg.extension)
     if #title > 0 then
         on_create_with_template(opts, title)
     end
@@ -2086,7 +2092,7 @@ local function CreateNote(opts)
     end
 
     local title = vim.fn.input("Title: ")
-    title = title:gsub("[" .. M.Cfg.extension .. "]+$", "")
+    title = strip_extension(title, M.Cfg.extension)
     if #title > 0 then
         on_create(opts, title)
     end