fix: Fix .stick class for older Webkit versions (#2995)

It looks like inputs had a light margin on older Webkit versions, making
the inputs slightly smaller than buttons in a .stick container.

Reference: https://github.com/FreshRSS/FreshRSS/pull/2938#issuecomment-632429861

p/themes/Alternative-Dark/template.css

@@ -220,6 +220,11 @@ td.numeric {
 	white-space: nowrap;
 }
 
+.stick > input {
+	margin-top: 0;
+	margin-bottom: 0;
+}
+
 .stick > input.long {
 	flex-shrink: 1;
 }

p/themes/Alternative-Dark/template.rtl.css

@@ -220,6 +220,11 @@ td.numeric {
 	white-space: nowrap;
 }
 
+.stick > input {
+	margin-top: 0;
+	margin-bottom: 0;
+}
+
 .stick > input.long {
 	flex-shrink: 1;
 }

p/themes/base-theme/template.css

@@ -225,6 +225,11 @@ td.numeric {
 	white-space: nowrap;
 }
 
+.stick > input {
+	margin-top: 0;
+	margin-bottom: 0;
+}
+
 .stick > input.long {
 	flex-shrink: 1;
 }

p/themes/base-theme/template.rtl.css

@@ -225,6 +225,11 @@ td.numeric {
 	white-space: nowrap;
 }
 
+.stick > input {
+	margin-top: 0;
+	margin-bottom: 0;
+}
+
 .stick > input.long {
 	flex-shrink: 1;
 }