Updated plugins, also experimenting with a new font

The font is IBM Plex Mono: https://ibm.github.io/type/

sources_non_forked/vim-go/autoload/go/tool.vim

@@ -162,6 +162,18 @@ function! go#tool#FilterValids(items) abort
 endfunction
 
 function! go#tool#ExecuteInDir(cmd) abort
+  " Verify that the directory actually exists. If the directory does not
+  " exist, then assume that the a:cmd should not be executed. Callers expect
+  " to check v:shell_error (via go#util#ShellError()), so execute a command
+  " that will return an error as if a:cmd was run and exited with an error.
+  " This helps avoid errors when working with plugins that use virtual files
+  " that don't actually exist on the file system (e.g. vim-fugitive's
+  " GitDiff).
+  if !isdirectory(expand("%:p:h"))
+    let [out, err] = go#util#Exec(["false"])
+    return ''
+  endif
+
   let old_gopath = $GOPATH
   let old_goroot = $GOROOT
   let $GOPATH = go#path#Detect()
@@ -194,7 +206,6 @@ function! go#tool#Exists(importpath) abort
     return 0
 endfunction
 
-
 " following two functions are from: https://github.com/mattn/gist-vim
 " thanks  @mattn
 function! s:get_browser_command() abort
@@ -202,12 +213,14 @@ function! s:get_browser_command() abort
     if go_play_browser_command == ''
         if go#util#IsWin()
             let go_play_browser_command = '!start rundll32 url.dll,FileProtocolHandler %URL%'
-        elseif has('mac') || has('macunix') || has('gui_macvim') || go#util#System('uname') =~? '^darwin'
+        elseif go#util#IsMac()
             let go_play_browser_command = 'open %URL%'
         elseif executable('xdg-open')
             let go_play_browser_command = 'xdg-open %URL%'
         elseif executable('firefox')
             let go_play_browser_command = 'firefox %URL% &'
+        elseif executable('chromium')
+            let go_play_browser_command = 'chromium %URL% &'
         else
             let go_play_browser_command = ''
         endif