Drop Emacs 26.x support

Emacs 27.x has been the stable version of Emacs for nearly a year, and
introduces a litany of bugfixes, performance, and quality-of-life
improvements that significantly reduce Doom's maintenance burden (like
XDG support, early-init.el, image manipulation without imagemagick, a
native JSON library, harfbuzz support, pdumper, and others).

With so many big changes on Doom's horizon, I like having one less (big)
thing to worry about.

Also reverts bb677cf7a (#5232) as it is no longer needed.

modules/tools/direnv/config.el

@@ -8,25 +8,20 @@
 
   (set-popup-rule! "^\\*envrc\\*" :quit t :ttl 0)
 
-  ;; I'm avoiding `global-envrc-mode' intentionally, because it has the
-  ;; potential to run too late in the mode startup process (and after, say,
-  ;; server hooks that may rely on that local direnv environment).
-  (add-hook! 'change-major-mode-after-body-hook
-    (defun +direnv-init-h ()
-      (unless (or envrc-mode
-                  (minibufferp)
-                  (file-remote-p default-directory))
-        (condition-case _
-            (envrc-mode 1)
-          (quit)))))
-
-  ;; Ensure these local variables survive major mode changes, so envrc-mode is
-  ;; only "activated" once per buffer.
-  (put 'envrc-mode 'permanent-local t)
-  (put 'envrc--status 'permanent-local t)
-  (put 'process-environment 'permanent-local t)
-  (put 'exec-path 'permanent-local t)
-  (put 'eshell-path-env 'permanent-local t)
+  ;; A globalized minor mode triggers on `after-change-major-mode-hook'
+  ;; normally, which runs after a major mode's body and hooks. If those hooks do
+  ;; any initialization work that's sensitive to environmental state set up by
+  ;; direnv, then you're gonna have a bad time, so I move the trigger to
+  ;; `change-major-mode-after-body-hook' instead. This runs before said hooks
+  ;; (but not the body; fingers crossed that no major mode does important env
+  ;; initialization there).
+  (add-hook! 'envrc-global-mode-hook
+    (defun +direnv-init-global-mode-earlier-h ()
+      (let ((fn #'envrc-global-mode-enable-in-buffers))
+        (if (not envrc-global-mode)
+            (remove-hook 'change-major-mode-after-body-hook fn)
+          (remove-hook 'after-change-major-mode-hook fn)
+          (add-hook 'change-major-mode-after-body-hook fn 100)))))
 
   (defadvice! +direnv--fail-gracefully-a (&rest _)
     "Don't try to use direnv if the executable isn't present."

modules/tools/lsp/+lsp.el

@@ -183,9 +183,9 @@ instead is more sensible."
         ;; and there is a bug preventing Flycheck errors from being shown (the
         ;; errors flash briefly and then disappear).
         lsp-ui-sideline-show-hover nil
-        ;; Some icons don't scale correctly on Emacs 26, so disable them there.
-        lsp-ui-sideline-actions-icon  ; DEPRECATED Remove later
-        (if EMACS27+ lsp-ui-sideline-actions-icon-default)
+        ;; Re-enable icon scaling (it's disabled by default upstream for Emacs
+        ;; 26.x compatibility; see emacs-lsp/lsp-ui#573)
+        lsp-ui-sideline-actions-icon t
         ;; REVIEW Temporarily disabled, due to immense slowness on every
         ;;        keypress. See emacs-lsp/lsp-ui#613
         lsp-ui-doc-enable nil)

modules/tools/pdf/config.el

@@ -126,9 +126,7 @@
   (defadvice! +pdf-suppress-large-file-prompts-a (orig-fn size op-type filename &optional offer-raw)
     :around #'abort-if-file-too-large
     (unless (string-match-p "\\.pdf\\'" filename)
-      (if offer-raw
-          (funcall orig-fn size op-type filename offer-raw)
-        (funcall orig-fn size op-type filename)))))
+      (funcall orig-fn size op-type filename offer-raw))))
 
 
 (use-package! saveplace-pdf-view