vimrc: Use consistent style for key mapping

This change updates portions of our vimrc that used inconsistent
capitalization for commands to have a more consistent style.

vimrc

@@ -106,16 +106,16 @@ set wildmode=list:longest,list:full
 function! InsertTabWrapper()
     let col = col('.') - 1
     if !col || getline('.')[col - 1] !~ '\k'
-        return "\<tab>"
+        return "\<Tab>"
     else
-        return "\<c-p>"
+        return "\<C-p>"
     endif
 endfunction
-inoremap <Tab> <c-r>=InsertTabWrapper()<cr>
-inoremap <S-Tab> <c-n>
+inoremap <Tab> <C-r>=InsertTabWrapper()<CR>
+inoremap <S-Tab> <C-n>
 
 " Switch between the last two files
-nnoremap <Leader><Leader> <c-^>
+nnoremap <Leader><Leader> <C-^>
 
 " Get off my lawn
 nnoremap <Left> :echoe "Use h"<CR>
@@ -131,7 +131,7 @@ nnoremap <silent> <Leader>a :TestSuite<CR>
 nnoremap <silent> <Leader>gt :TestVisit<CR>
 
 " Run commands that require an interactive shell
-nnoremap <Leader>r :RunInInteractiveShell<space>
+nnoremap <Leader>r :RunInInteractiveShell<Space>
 
 " Treat <li> and <p> tags like the block tags they are
 let g:html_indent_tags = 'li\|p'