Fix failure with did_you_mean in bundle install.

Deploying to production failed during `bundle install` because of an
incompatibility between did_you_mean-1.3.0 + ruby-2.6 + rubygems-3.0 +
bundler-2.0.

ref: `https://github.com/yuki24/did_you_mean/issues/117#issuecomment-482565387`

Gemfile

@@ -45,7 +45,7 @@ gem 'retriable'
 gem 'redis'
 gem 'request_store'
 gem 'builder'
-gem 'did_you_mean'
+# gem 'did_you_mean' # github.com/yuki24/did_you_mean/issues/117
 gem 'term-ansicolor', require: "term/ansicolor"
 
 # needed for looser jpeg header compat

Gemfile.lock

@@ -124,7 +124,6 @@ GEM
     delayed_job_active_record (4.1.3)
       activerecord (>= 3.0, < 5.3)
       delayed_job (>= 3.0, < 5)
-    did_you_mean (1.3.0)
     diff-lcs (1.3)
     docile (1.3.2)
     domain_name (0.5.20190701)
@@ -463,7 +462,6 @@ DEPENDENCIES
   dalli
   delayed_job
   delayed_job_active_record
-  did_you_mean
   diff-lcs
   dotenv-rails
   dtext_rb!