Some deprecation fixes

Author: ezhang887

alacritty.toml

@@ -1,6 +1,3 @@
-alt_send_esc = true
-custom_cursor_colors = true
-enable_experimental_conpty_backend = false
 live_config_reload = true
 working_directory = "None"
 
@@ -43,12 +40,10 @@ unfocused_hollow = true
 log_level = "Warn"
 persistent_logging = false
 print_events = false
-ref_test = false
 render_timer = false
 
 [font]
 size = 11.0
-use_thin_strokes = true
 
 [font.glyph_offset]
 x = 0
@@ -590,12 +585,6 @@ hide_when_typing = false
 action = "PasteSelection"
 mouse = "Middle"
 
-[mouse.double_click]
-threshold = 300
-
-[mouse.triple_click]
-threshold = 300
-
 [scrolling]
 history = 10000
 multiplier = 3
@@ -613,6 +602,7 @@ decorations = "full"
 dynamic_padding = false
 opacity = 1.0
 startup_mode = "Windowed"
+option_as_alt = "Both"
 
 [window.dimensions]
 columns = 0