feat: Allow hiding mappings from the help panel (#278)

Co-authored-by: Sindre T. Strøm <sindrets@gmail.com>

Author: fjchen7

README.md

@@ -68,7 +68,7 @@ set of paths, and view the changes made in a diff split. This is a porcelain
 interface for git-log, and supports a good number of its options. Things like:
 
 - Filtering commits by grepping commit messages and commit authors.
-- Tracing the line evolution of a given set of line ranges for multiple files. 
+- Tracing the line evolution of a given set of line ranges for multiple files.
 - Only listing changes for a specific commit range, branch, or tag.
 - Following file changes through renames.
 
@@ -175,7 +175,7 @@ require("diffview").setup({
   },
   view = {
     -- Configure the layout and behavior of different types of views.
-    -- Available layouts: 
+    -- Available layouts:
     --  'diff1_plain'
     --    |'diff2_horizontal'
     --    |'diff2_vertical'

doc/diffview.txt

@@ -651,6 +651,15 @@ keymaps                                         *diffview-config-keymaps*
         }
 <
 
+        Setting a mapping's `desc` field to `"diffview_ignore"` will hide the
+        mapping from the help panel: >
+
+        view = {
+          -- Ignore mapping in the help panel
+          { "n", "<2-LeftMouse>", actions.select_entry, { desc = "diffview_ignore" } },
+        }
+<
+
         To disable all the default mappings simply set: >
 
         keymaps = {

lua/diffview/ui/panels/help_panel.lua

@@ -149,7 +149,6 @@ function HelpPanel:update_components()
         return a < b
       end)
 
-      height = height + #maps + 3
       local items = { name = "items" }
       local section_schema = {
         name = "section",
@@ -163,17 +162,22 @@ function HelpPanel:update_components()
       }
 
       for _, mapping in ipairs(maps) do
-        width = math.max(width, 14 + 4 + #mapping[5] + 2)
-        table.insert(items, {
-          name = "item",
-          context = {
-            label_lhs = ("%14s"):format(mapping[2]),
-            label_rhs = ("%s"):format(mapping[5]),
-            mapping = mapping,
-          },
-        })
+        local desc = mapping[5]
+
+        if desc ~= "diffview_ignore" then
+          width = math.max(width, 14 + 4 + #mapping[5] + 2)
+          table.insert(items, {
+            name = "item",
+            context = {
+              label_lhs = ("%14s"):format(mapping[2]),
+              label_rhs = desc,
+              mapping = mapping,
+            },
+          })
+        end
       end
 
+      height = height + #items + 3
       table.insert(sections, section_schema)
     end